Century Aluminum (CENX) 10-Q 6 May 16 2016 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2016	Apr. 28, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	CENTURY ALUMINUM CO
Entity Central Index Key	949,157
Document Type	10-Q
Document Period End Date	Mar. 31, 2016
Amendment Flag	false
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		87,059,733

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
NET SALES:
Related parties	$ 280,377	$ 575,729
Third-party customers	38,477	12,182
Total net sales	318,854	587,911
Cost of goods sold	321,906	493,816
Gross profit (loss)	(3,052)	94,095
Selling, general and administrative expenses	9,625	11,971
Other operating expense - net	881	2,079
Operating income (loss)	(13,558)	80,045
Interest expense	(5,493)	(5,551)
Interest income	114	142
Net gain on forward and derivative contracts	353	353
Unrealized gain on fair value of contingent consideration	0	6,527
Other income (expense) - net	(6)	1,054
Income (loss) before income taxes and equity in earnings of joint ventures	(18,590)	82,570
Income tax benefit (expense)	2,070	(9,301)
Income (loss) before equity in earnings of joint ventures	(16,520)	73,269
Equity in earnings of joint ventures	357	510
Net income (loss)	(16,163)	73,779
Net income (loss) allocated to common stockholders	$ (16,163)	$ 67,813
EARNINGS (LOSS) PER COMMON SHARE:
Basic and Diluted (in dollars per share)	$ (0.19)	$ 0.76
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING:
Basic (shares)	87,040	88,814
Diluted (shares)	87,040	89,369

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net income (loss)	$ (16,163)	$ 73,779
Other comprehensive income (loss) before income tax effect:
Net gain on foreign currency cash flow hedges reclassified as income	(46)	(47)
Defined benefit plans and other postretirement benefits:
Amortization of prior service benefit during the period	(667)	(936)
Amortization of actuarial net loss during the period	1,919	1,444
Other comprehensive income before income tax effect	1,206	461
Income tax effect	(383)	(383)
Other comprehensive income	823	78
Total comprehensive income (loss)	$ (15,340)	$ 73,857

CONSOLIDATED BALANCE SHEETS (Un

CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
ASSETS
Cash and cash equivalents	$ 126,461	$ 115,393
Restricted cash	795	791
Accounts receivable - net	12,668	9,475
Due from affiliates	15,478	17,417
Inventories	220,502	231,872
Prepaid and other current assets	29,622	42,412
Assets held for sale	29,715	30,697
Total current assets	435,241	448,057
Property, plant and equipment - net	1,215,222	1,232,256
Other assets	73,142	72,155
TOTAL	1,723,605	1,752,468
LIABILITIES:
Accounts payable, trade	84,587	90,489
Due to affiliates	6,173	10,045
Accrued and other current liabilities	50,169	48,822
Accrued employee benefits costs	10,054	10,148
Industrial revenue bonds	7,815	7,815
Total current liabilities	158,798	167,319
Senior notes payable	247,380	247,278
Accrued pension benefits costs - less current portion	43,437	43,999
Accrued postretirement benefits costs - less current portion	125,941	125,999
Other liabilities	51,799	53,009
Deferred taxes	93,399	96,994
Total noncurrent liabilities	$ 561,956	$ 567,279
COMMITMENTS AND CONTINGENCIES
SHAREHOLDERS’ EQUITY:
Preferred stock	$ 1	$ 1
Common stock	942	942
Additional paid-in capital	2,513,952	2,513,631
Treasury stock, at cost	(86,276)	(86,276)
Accumulated other comprehensive loss	(111,827)	(112,650)
Accumulated deficit	(1,313,941)	(1,297,778)
Total shareholders’ equity	1,002,851	1,017,870
TOTAL	$ 1,723,605	$ 1,752,468

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ (16,163)	$ 73,779
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Unrealized gain on fair value of contingent consideration	0	(6,527)
Unrealized gain on E.ON contingent obligation	(353)	(353)
Lower of cost or market inventory adjustment	(5,784)	0
Depreciation and amortization	21,260	18,131
Pension and other postretirement benefits	632	(984)
Deferred income taxes	(3,587)	8,851
Stock-based compensation	321	405
Equity in earnings of joint ventures	(357)	(510)
Change in operating assets and liabilities:
Accounts receivable - net	(3,193)	72,702
Due from affiliates	1,939	(53,559)
Inventories	17,648	(14,335)
Prepaid and other current assets	14,290	5,960
Accounts payable, trade	(5,983)	(18,508)
Due to affiliates	(5,372)	27,773
Accrued and other current liabilities	1,253	2,874
Other - net	(1,648)	568
Net cash provided by operating activities	14,903	116,267
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property, plant and equipment	(3,835)	(12,627)
Restricted and other cash deposits	0	(21,012)
Net cash used in investing activities	(3,835)	(33,639)
CASH FLOWS FROM FINANCING ACTIVITIES:
Borrowings under revolving credit facilities	371	455
Repayments under revolving credit facilities	(371)	(455)
Repurchase of common stock	0	(19,439)
Net cash used in financing activities	0	(19,439)
CHANGE IN CASH AND CASH EQUIVALENTS	11,068	63,189
Cash and cash equivalents, beginning of period	115,393	163,242
Cash and cash equivalents, end of period	$ 126,461	$ 226,431

General

General	3 Months Ended
	Mar. 31, 2016
General [Abstract]
General	General The accompanying unaudited interim consolidated financial statements of Century Aluminum Company should be read in conjunction with the audited consolidated financial statements for the year ended December 31, 2015 . In management’s opinion, the unaudited interim consolidated financial statements reflect all adjustments, which are of a normal and recurring nature, that are necessary for a fair presentation of financial results for the interim periods presented. Operating results for the first three months of 2016 are not necessarily indicative of the results that may be expected for the year ending December 31, 2016 . Throughout this Form 10-Q, and unless expressly stated otherwise or as the context otherwise requires, "Century Aluminum," "Century," the "Company", "we," "us," "our" and "ours" refer to Century Aluminum Company and its consolidated subsidiaries.

Related party transactions

Related party transactions	3 Months Ended
	Mar. 31, 2016
Related Party Transactions [Abstract]
Related party transactions	Related party transactions Our significant related party transactions occurring during the three months ended March 31, 2016 and 2015 are described below. We believe that all of the transactions with our related parties were at prices that approximate market. Glencore ownership As of March 31, 2016 , Glencore plc and its affiliates (together "Glencore") own 42.9% of Century’s outstanding common stock and all of our outstanding Series A Convertible Preferred stock. Through its ownership of our common and preferred stock, Glencore has an overall 47.5% economic ownership in Century Aluminum. Sales to Glencore We entered into an agreement with Glencore pursuant to which we agreed to sell, and Glencore agreed to purchase, substantially all of our primary aluminum production in North America for 2015 and 2016 on a take-or-pay basis at prices determined by reference to the Midwest Transaction Price plus additional negotiated product premiums. The current term of the agreement continues through December 31, 2016. In addition, we recently reached an agreement to sell Glencore approximately 24,500 tonnes of molten aluminum during 2017 at prices based on the Midwest Transaction Price. We sell primary aluminum produced at our Grundartangi facility under a long-term sales contract through 2017 with Glencore at prices based on the London Metal Exchange ("LME") price for primary aluminum plus the European Duty Paid premium and any applicable product premiums. We also receive tolling fees from Glencore under tolling agreements that provide for delivery of primary aluminum produced at our Grundartangi facility through June 2016. The fee paid by Glencore under these tolling agreements is based on the LME price for primary aluminum plus a portion of the European Duty Paid premium. Glencore purchases the aluminum we produce for resale to end users. Purchases from Glencore We purchase alumina from Glencore on both a spot basis and under a long-term supply agreement. Glencore has agreed to supply us with alumina under a long-term supply agreement through 2017 at prices indexed to the LME price of primary aluminum or based on a published alumina index. In 2015 and 2016 our purchases from Glencore have been based on a published alumina index. Transactions with Baise Haohai Carbon Co., Ltd. ("BHH") We own a 40% stake in BHH, a joint venture that owns a carbon anode and cathode facility located in the Guangxi Zhuang Autonomous Region of south China. We purchase carbon anodes from BHH. In the fourth quarter of 2015, we completed the construction of a second furnace at our carbon anode facility in Vlissingen, Netherlands. This investment increased our capacity to produce carbon anodes and significantly reduced the quantity of carbon anodes that we source from BHH. As a result, in the fourth quarter of 2015, we made the decision to pursue an exit from our investment in BHH and recorded an $11,584 impairment loss. Summary A summary of the aforementioned significant related party transactions for the three months ended March 31, 2016 and 2015 is as follows: Three months ended March 31, 2016 2015 Net sales to Glencore $ 280,377 $ 575,729 Purchases from Glencore 44,013 107,814 Purchases from BHH 2,383 14,820

Business acquisitions

Business acquisitions	3 Months Ended
	Mar. 31, 2016
Business Combinations [Abstract]
Business acquisitions	Business acquisitions Acquisition of Mt. Holly aluminum smelter On October 23, 2014, our wholly-owned subsidiary, Berkeley Aluminum Inc. ("Berkeley") entered into a stock purchase agreement (the "Stock Purchase Agreement") with Alumax Inc. ("Alumax"), a wholly-owned subsidiary of Alcoa Inc. ("Alcoa"), pursuant to which Berkeley acquired all of the issued and outstanding shares of Alumax of South Carolina, Inc. ("Alumax of SC") and thereby acquired Alcoa’s 50.3% stake in Mt. Holly. Berkeley had previously owned 49.7% of Mt. Holly. Immediately following the consummation of the transaction on December 1, 2014, Berkeley merged with and into Alumax of SC with Alumax of SC surviving and changing its name to Century Aluminum of South Carolina, Inc. ("CASC"). Following the consummation of the transaction, CASC owns 100% of Mt. Holly. Mt. Holly, located in Goose Creek, South Carolina, employed approximately 600 people and had an annual production capacity of 231,000 tonnes of primary aluminum as of the acquisition date. Pursuant to the terms of the Stock Purchase Agreement, Berkeley acquired all of the issued and outstanding shares of capital stock of Alumax of SC for $67,500 in cash subject to a contingent earn-out payment, working capital and other similar adjustments. The acquisition was funded with available cash on hand. We incurred acquisition-related costs for Mt. Holly of $1,539 which were expensed to selling, general and administrative expenses in the period that they were incurred. The following table summarizes all of the elements of purchase consideration for the transaction as of December 1, 2014. Purchase price $ 67,500 Contingent consideration 13,780 Economic, working capital and other closing adjustments (13,513 ) Total consideration $ 67,767 Contingent Consideration - Earn-out provision The Stock Purchase Agreement provided for a contingent cash payment to be made following December 31, 2015. We measured the fair value of contingent consideration and recognized a $13,780 liability at the closing date. Each period, until the end of the measurement period on December 31, 2015, we remeasured the fair value of the contingent consideration and the change in the fair value was recognized in earnings. We recognized gains, primarily related to decreases in the forward curve of the LME price of primary aluminum, of $7,943 and $18,337 during the twelve month periods ended December 31, 2014 and 2015, respectively, $6,527 of which was recognized during the three month period ended March 31, 2015. Alcoa paid us $12,500 in settlement of the contingent consideration in March 2016. Economic Adjustment, working capital and other adjustments The Stock Purchase Agreement provided for an economic adjustment that was established to put the parties in the same economic position as if the closing date for the acquisition had occurred on September 30, 2014. We received $11,189 from Alcoa for the economic adjustment in April 2015. The Stock Purchase Agreement also contained provisions for a payment for working capital adjustments based on actual working capital at closing compared to established working capital targets. We received $124 from Alcoa for the working capital adjustments in April 2015. Other adjustments include $200 due to Alcoa and amounts due to CASC for expected future post-employment benefit payments and certain other items. We received $2,400 from Alcoa for these other adjustments at closing. Net cash consideration The total net cash consideration paid to Alcoa after final resolution of all post-closing adjustments, including the earn-out provision, was $41,487 .

Fair value measurements

Fair value measurements	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Fair value measurements	Fair value measurements The following section describes the valuation methodology used to measure our financial assets and liabilities that were accounted for at fair value and are categorized based on the fair value hierarchy described in Accounting Standards Codification ("ASC") 820, "Fair Value Measurements and Disclosures." Overview of Century’s valuation methodology Level Significant inputs Cash equivalents 1 Quoted market prices Trust assets (1) 1 Quoted market prices Surety bonds 1 Quoted market prices E.ON contingent obligation 3 Quoted LME forward market, management’s estimates of the LME forward market prices for periods beyond the quoted periods and management’s estimate of future level of operations (1) Trust assets are currently invested in money market funds. These trust assets are held to fund the non-qualified supplemental executive pension benefit obligations for certain of our officers. The trust has sole authority to invest the funds in secure interest producing investments consisting of short-term securities issued or guaranteed by the United States government or cash and cash equivalents. Our fair value measurements include the consideration of market risks that other market participants might consider in pricing the particular asset or liability, specifically non-performance risk and counterparty credit risk. Considerations of the non-performance risk and counterparty credit risk are used to establish the appropriate risk-adjusted discount rates used in our fair value measurements. Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of fair value assets and liabilities and the placement within the fair value hierarchy levels. There were no transfers between Level 1 and 2 during the periods presented. There were no transfers into or out of Level 3 during the periods presented. It is our policy to recognize transfers into and transfers out of Level 3 as of the date of the event or change in circumstances that caused the transfer. The following table sets forth our financial assets and liabilities that were accounted for at fair value on a recurring basis by the level of input within the ASC 820 fair value hierarchy. Recurring Fair Value Measurements As of March 31, 2016 Level 1 Level 2 Level 3 Total ASSETS: Cash equivalents $ 120,061 $ — $ — $ 120,061 Trust assets 4,789 — — 4,789 Surety bonds 1,870 — — 1,870 TOTAL $ 126,720 $ — $ — $ 126,720 LIABILITIES: E.ON contingent obligation - net $ — $ — $ — $ — TOTAL $ — $ — $ — $ — Recurring Fair Value Measurements As of December 31, 2015 Level 1 Level 2 Level 3 Total ASSETS: Cash equivalents $ 102,675 $ — $ — $ 102,675 Trust assets 5,226 — — 5,226 Surety bonds 1,870 — — 1,870 TOTAL $ 109,771 $ — $ — $ 109,771 LIABILITIES: E.ON contingent obligation – net $ — $ — $ — $ — TOTAL $ — $ — $ — $ —

Earnings (loss) per share

Earnings (loss) per share	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Earnings (loss) per share	Earnings (loss) per share Basic earnings (loss) per share ("EPS") amounts are calculated by dividing net income (loss) allocated to common stockholders by the weighted average number of common shares outstanding. Diluted EPS amounts assume the issuance of common stock for all potentially dilutive common shares outstanding. The following table shows the basic and diluted earnings (loss) per share for the three months ended March 31, 2016 and 2015 : For the three months ended March 31, 2016 2015 Loss Shares (000) Per-Share Income Shares (000) Per-Share Net income (loss) $ (16,163 ) $ 73,779 Amount allocated to common stockholders 100.00 % 91.91 % Basic EPS: Net income (loss) allocated to common stockholders (16,163 ) 87,040 $ (0.19 ) 67,813 88,814 $ 0.76 Effect of Dilutive Securities: Share-based compensation plans — — — 555 Diluted EPS: Net income (loss) allocated to common stockholders $ (16,163 ) 87,040 $ (0.19 ) $ 67,813 89,369 $ 0.76 Securities excluded from the calculation of diluted EPS: Three months ended March 31, 2016 2015 Stock options (1) 393,237 333,266 Service-based share awards (1) 498,809 — (1) In periods when we report a net loss, all share awards are excluded from the calculation of diluted weighted average shares outstanding because of their antidilutive effect on earnings (loss) per share. In periods when we report net income, certain option awards may be excluded from the calculation of diluted EPS if the exercise price of the option award was greater than the average market price of the underlying common stock.

Shareholders' equity

Shareholders' equity	3 Months Ended
	Mar. 31, 2016
Stockholders' Equity Note [Abstract]
Shareholders' equity	Shareholders’ equity Common Stock As of March 31, 2016 and December 31, 2015 , we had 195,000,000 shares of common stock, $0.01 cent par value, authorized under our Restated Certificate of Incorporation, of which 94,246,254 shares were issued and 87,059,733 shares were outstanding at March 31, 2016; 94,224,571 shares were issued and 87,038,050 shares were outstanding at December 31, 2015. The rights, preferences and privileges of holders of our common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of our preferred stock which are currently outstanding, including our Series A Convertible Preferred Stock, or which we may designate and issue in the future. Stock Repurchase Program In 2011, our Board of Directors approved a $60,000 common stock repurchase program which was expanded in 2015 to $130,000 . Through December 31, 2015 we had repurchased 7,186,521 shares of common stock for an aggregate purchase price of $86,276 . There have been no share repurchases since April 2015 and we have $43,724 remaining under the repurchase program authorization. The repurchase program may be expanded, suspended or discontinued by our Board, in its sole discretion, at any time. Shares of common stock repurchased are recorded at cost as treasury stock and result in a reduction of shareholders’ equity in the consolidated balance sheets. From time to time, treasury shares may be reissued as contributions to our employee benefit plans and for the conversion of convertible preferred stock. When shares are reissued, we use an average cost method for determining cost. The difference between the cost of the shares and the reissuance price is added to or deducted from additional paid-in capital. Preferred Stock As of March 31, 2016 and December 31, 2015 we had 5,000,000 shares of preferred stock, $0.01 cent par value per share, authorized under our Restated Certificate of Incorporation. In 2008, we issued 160,000 shares of our Series A Convertible Preferred Stock, all of which is held by Glencore, and at March 31, 2016 and December 31, 2015 , 76,446 and 76,539 shares were outstanding, respectively. The issuance of common stock under our stock incentive programs, debt exchange transactions and any stock offering that excludes Glencore participation triggers anti-dilution provisions of the preferred stock agreement and results in the automatic conversion of Series A Convertible Preferred Stock shares into shares of common stock. The conversion of preferred to common shares is 100 shares of common for each share of preferred stock. Our Series A Convertible Preferred Stock has a par value of $0.01 per share. Our Board of Directors may issue preferred stock in one or more series and determine for each series the dividend rights, conversion rights, voting rights, redemption rights, liquidation preferences, sinking fund terms and the number of shares constituting that series, as well as the designation thereof. Depending upon the terms of preferred stock established by our Board of Directors, any or all of the preferred stock could have preference over the common stock with respect to dividends and other distributions and upon the liquidation of Century. In addition, issuance of any shares of preferred stock with voting powers may dilute the voting power of the outstanding common stock. The Common and Preferred Stock Activity table below contains additional information about preferred stock conversions during the three months ended March 31, 2016 and 2015 . Common and Preferred Stock Activity: Preferred stock Common stock (in shares) Series A convertible Treasury Outstanding Beginning balance as of December 31, 2015 76,539 7,186,521 87,038,050 Repurchase of common stock — — — Conversion of convertible preferred stock (93 ) — 9,305 Issuance for share-based compensation plans — — 12,378 Ending balance as of March 31, 2016 76,446 7,186,521 87,059,733 Beginning balance as of December 31, 2014 78,141 4,786,521 89,064,582 Repurchase of common stock — 1,200,000 (1,200,000 ) Conversion of convertible preferred stock (80 ) — 7,947 Issuance for share-based compensation plans — — 10,828 Ending balance as of March 31, 2015 78,061 5,986,521 87,883,357

Income taxes

Income taxes	3 Months Ended
	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Income taxes	Income taxes We recorded an income tax benefit for the three months ended March 31, 2016 of $2,070 which primarily consisted of foreign income tax benefits. Our U.S. and certain foreign deferred tax assets, net of deferred tax liabilities, are subject to a valuation allowance. We recorded income tax expense for the three months ended March 31, 2015 of $9,301 which primarily consisted of foreign and state income taxes. Our income tax benefit or expense is based on an annual effective tax rate forecast, including estimates and assumptions that could change during the year. The application of the requirements for accounting for income taxes in interim periods, after consideration of our valuation allowance, causes a significant variation in the typical relationship between income tax expense and pretax accounting income. As of March 31, 2016 , all of Century's U.S. and certain foreign deferred tax assets, net of deferred tax liabilities, continue to be subject to a valuation allowance.

Inventories

Inventories	3 Months Ended
	Mar. 31, 2016
Inventory, Net [Abstract]
Inventories	Inventories Inventories consist of the following: March 31, 2016 December 31, 2015 Raw materials $ 54,914 $ 52,121 Work-in-process 28,302 34,025 Finished goods 18,821 15,988 Operating and other supplies 118,465 129,738 Total inventories $ 220,502 $ 231,872 Inventories are stated at the lower of cost or market using the first-in, first out method.

Debt

Debt	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Debt	Debt March 31, 2016 December 31, 2015 Debt classified as current liabilities: Hancock County industrial revenue bonds ("IRBs") due 2028, interest payable quarterly (variable interest rates (not to exceed 12%)) (1) $ 7,815 $ 7,815 Debt classified as non-current liabilities: 7.5% senior secured notes due June 1, 2021, net of debt discount of $2,620 and $2,722, respectively, interest payable semiannually 247,380 247,278 Total $ 255,195 $ 255,093 (1) The IRBs are classified as current liabilities because they are remarketed weekly and could be required to be repaid upon demand if there is a failed remarketing. The IRB interest rate at March 31, 2016 was 0.59% . U.S. Revolving Credit Facility General . We and certain of our direct and indirect domestic subsidiaries are party to a senior secured revolving credit facility, dated May 24, 2013, as amended, with a syndicate of lenders which provides for borrowings of up to $150,000 in the aggregate, including up to $110,000 under a letter of credit sub-facility (the "U.S. revolving credit facility"). Our U.S. revolving credit facility matures in June 2020. Any letters of credit issued and outstanding under the U.S. revolving credit facility reduce our borrowing availability on a dollar-for-dollar basis. The availability of funds under the U.S. revolving credit facility is limited by a specified borrowing base consisting of accounts receivable, inventory and qualified cash deposits of the borrowers which meet the eligibility criteria. Status of our U.S. revolving credit facility: March 31, 2016 Credit facility maximum amount $ 150,000 Borrowing availability 85,844 Outstanding letters of credit issued 44,759 Outstanding borrowings — Borrowing availability, net of outstanding letters of credit and borrowings 41,085 Iceland Revolving Credit Facility General . We have also entered into, through our wholly-owned subsidiary Nordural Grundartangi ehf, a $50 million revolving credit facility, dated November 27, 2013 (the "Iceland revolving credit facility"). The Iceland revolving credit facility was renewed in April 2016 with the term extended through November 27, 2018. The availability of funds under the Iceland revolving credit facility is limited by a specified borrowing base consisting of inventory and accounts receivable of Grundartangi. Status of our Iceland revolving credit facility: March 31, 2016 Credit facility maximum amount $ 50,000 Borrowing availability 45,397 Outstanding borrowings — Borrowing availability, net of borrowings 45,397 7.5% Notes due 2021 General. On June 4, 2013, we issued $250,000 of our 7.5% Notes due June 1, 2021 (the "2021 Notes") in a private offering exempt from the registration requirements of the Securities Act of 1933, as amended. The 2021 Notes were issued at a discount and bear interest at the rate of 7.5% per annum on the principal amount, payable semi-annually in arrears in cash on June 1st and December 1st of each year. Fair Value. Fair value for our 2021 Notes was based on the latest trading data available and was $184,063 and $169,220 , as of March 31, 2016 and December 31, 2015 , respectively. Although we use quoted market prices for identical debt instruments, the markets on which they trade are not considered to be active and are therefore considered Level 2 fair value measurements.

Commitments and contingencies

Commitments and contingencies	3 Months Ended
	Mar. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	Commitments and contingencies Environmental Contingencies Based upon all available information, we believe our current environmental liabilities do not have, and are not likely to have, a material adverse effect on our financial condition, results of operations or liquidity. However, because of the inherent uncertainties in estimating environmental liabilities primarily due to unknown facts and circumstances and changing governmental regulations and legal standards regarding liability, there can be no assurance that future capital expenditures and costs for environmental compliance at currently or formerly owned or operated properties will not result in liabilities that may have a material adverse effect on our financial condition, results of operations or liquidity. It is our policy to accrue for costs associated with environmental assessments and remedial efforts when it becomes probable that a liability has been incurred and the costs can be reasonably estimated. The aggregate environmental-related accrued liabilities were $ 1,248 and $ 1,112 at March 31, 2016 and December 31, 2015 , respectively. All accrued amounts have been recorded without giving effect to any possible future recoveries. Costs for ongoing environmental compliance, including maintenance and monitoring are expensed as incurred. In July 2006, we were named as a defendant, together with certain affiliates of Alcan Inc., in a lawsuit brought by Alcoa Inc. seeking to determine responsibility for certain environmental indemnity obligations related to the sale of a cast aluminum plate manufacturing facility located in Vernon, California, which we purchased from Alcoa Inc. in December 1998, and sold to Alcan Rolled Products-Ravenswood LLC in July 1999. The complaint also seeks costs and attorney fees. The matter is in a preliminary stage in the U.S. District Court for the District of Delaware, and we cannot predict the ultimate outcome of this action or estimate a range of possible losses related to this matter at this time. Matters relating to the St. Croix Alumina Refining Facility We are a party to a United States Environmental Protection Agency Administrative Order on Consent (the "Order") pursuant to which certain past and present owners of an alumina refining facility at St. Croix, Virgin Islands (the "St. Croix Alumina Refinery") have agreed to carry out a Hydrocarbon Recovery Plan to remove and manage hydrocarbons floating on groundwater underlying the facility. Pursuant to the Hydrocarbon Recovery Plan, recovered hydrocarbons and groundwater are delivered to the adjacent petroleum refinery where they are received and managed. In connection with the sale of the facility by Lockheed Martin Corporation ("Lockheed") to one of our affiliates, Virgin Islands Alumina Corporation ("Vialco"), in 1989, Lockheed, Vialco and Century entered into the Lockheed-Vialco Asset Purchase Agreement. The indemnity provisions contained in the Lockheed-Vialco Asset Purchase Agreement allocate responsibility for certain environmental matters. Lockheed has tendered indemnity to Vialco. We have likewise tendered indemnity to Lockheed. Through March 31, 2016 , we have expended approximately $ 1,085 on the Hydrocarbon Recovery Plan. At this time, we are not able to estimate the amount of any future potential payments under this indemnification to comply with the Order, but we do not anticipate that any such amounts will have a material adverse effect on our financial condition, results of operations or liquidity, regardless of the final outcome. Vialco sold the St. Croix Alumina Refinery to St. Croix Alumina, LLC, a subsidiary of Alcoa, in 1995. In December 2010, Century was among several defendants named in a lawsuit filed by plaintiffs who either worked, resided or owned property in the area downwind from the St. Croix Alumina Refinery. In March 2011, Century was also named a defendant in a nearly identical suit brought by certain additional plaintiffs. The plaintiffs in both suits allege damages caused by the presence of red mud and other particulates coming from the alumina facility and are seeking unspecified monetary damages, costs and attorney fees as well as certain injunctive relief. We tendered indemnity and defense to St. Croix Alumina LLC and Alcoa Alumina & Chemical LLC under the terms of an acquisition agreement relating to the facility and have filed motions to dismiss plaintiffs’ claims. In August 2015, the Superior Court of the Virgin Islands, Division of St. Croix denied the motions to dismiss but ordered all plaintiffs to refile individual complaints. At this time, it is not possible to predict the ultimate outcome of or to estimate a range of possible losses for any of the foregoing actions relating to the St. Croix Alumina Refinery. Legal Contingencies In addition to the foregoing matters, we have pending against us or may be subject to various lawsuits, claims and proceedings related primarily to employment, commercial, stockholder, safety and health matters. While the results of such litigation matters and claims cannot be predicted with certainty, we believe that the final outcome of such matters will not have a material adverse impact on our financial condition, results of operations or liquidity. However, because of the nature and inherent uncertainties of litigation, should the outcome of these actions be unfavorable, our business, financial condition, results of operations and liquidity could be materially and adversely affected. In evaluating whether to accrue for losses associated with legal contingencies, it is our policy to take into consideration factors such as the facts and circumstances asserted, our historical experience with contingencies of a similar nature, the likelihood of our prevailing and the severity of any potential loss. For some matters, no accrual is established because we have assessed our risk of loss to be remote. Where the risk of loss is probable and the amount of the loss can be reasonably estimated, we record an accrual, either on an individual basis or with respect to a group of matters involving similar claims, based on the factors set forth above. When we have assessed that a loss associated with legal contingencies is reasonably possible, we determine if estimates of possible losses or ranges of possible losses are in excess of related accrued liabilities, if any. Based on current knowledge, management has ascertained estimates for losses that are reasonably possible and management does not believe that any reasonably possible outcomes in excess of our accruals, if any, either individually or in aggregate, would be material to our financial condition, results of operations or liquidity. We reevaluate and update our assessments and accruals as matters progress over time. Ravenswood Retiree Medical Benefits changes In November 2009, Century Aluminum of West Virginia ("CAWV") filed a class action complaint for declaratory judgment against the United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union ("USW"), the USW’s local and certain CAWV retirees, individually and as class representatives, seeking a declaration of CAWV’s rights to modify/terminate retiree medical benefits. Later in November 2009, the USW and representatives of a retiree class filed a separate suit against CAWV, Century Aluminum Company, Century Aluminum Master Welfare Benefit Plan, and various John Does with respect to the foregoing. These actions, entitled Dewhurst, et al. v. Century Aluminum Co., et al., and Century Aluminum of West Virginia, Inc. v. United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union, AFL-CIO/CLC, et al., have been consolidated and venue has been set in the District Court for the Southern District of West Virginia. In September 2015, the trial court granted CAWV's motion for summary judgment of these actions. The trial court decision is currently being appealed by the USW to the Court of Appeals for the 4th Circuit. PBGC Settlement In April 2013, we entered into a settlement agreement with the Pension Benefit Guarantee Corporation ("PBGC") regarding an alleged "cessation of operations" at our Ravenswood facility as a result of the curtailment of operations at the facility and, pursuant to the agreement, we agreed to make additional contributions (above any minimum required contributions) to our defined benefit pension plans totaling approximately $17.4 million . The agreement permits us to defer payments during periods of lower primary aluminum prices relative to our cost of operations. We remeasure aluminum prices against our cost of operations on an annual basis based on our fourth quarter results. To the extent that we elect to defer one or more of these payments, we are required to provide the PBGC with acceptable security for any such deferred payments. We made contributions pursuant to this agreement of $1.1 million in March 2015 and $6.7 million in 2013. We did not make any contributions during 2014. The remaining contributions under this agreement are approximately $9.6 million . Power Commitments and Contingencies Hawesville Hawesville has a power supply arrangement with Kenergy and EDF Trading North America, LLC (“EDF") which provides market-based power to the Hawesville smelter. Under this arrangement, the power companies purchase power on the open market and pass it through to Hawesville at Midcontinent Independent System Operator ("MISO") pricing plus transmission and other costs. The power supply arrangement with Kenergy has an effective term through December 2023. The arrangement with EDF to act as our market participant with MISO has an effective term through May 2017, extending year to year thereafter unless a one year notice is given. Sebree Sebree has a power supply arrangement with Kenergy and EDF which provides market-based power to the Sebree smelter. Similar to the arrangement at Hawesville, the power companies purchase power on the open market and pass it through to Sebree at MISO pricing plus transmission and other costs. The power supply arrangement with Kenergy has an effective term through December 2023. The arrangement with EDF to act as our market participant with MISO has an effective term through May 2017, extending year to year thereafter unless a one year notice is given. Mt. Holly CASC's former power agreement with the South Carolina Public Service Authority ("Santee Cooper") for power to the Mt. Holly smelter expired on December 31, 2015. Mt. Holly is currently operating at 50% capacity under a short-term power arrangement while CASC works on a long-term solution that would allow Mt. Holly to access market power for all its power supply requirements. This short-term agreement with Santee Cooper provides for the supply of power to Mt. Holly from two sources: (1) 25% of the Mt. Holly load is served from Santee Cooper’s generation at a standard cost-based industrial rate and (2) 75% of the Mt. Holly load is sourced from a third party supplier from generation that is outside Santee Cooper’s service territory at market prices that are tied to natural gas prices. CASC pays a third party for transmission services to Santee Cooper’s system and pays Santee Cooper its standard transmission tariff for transmission services to Mt. Holly. The agreement with Santee Cooper has a term through December 31, 2018 but can be terminated by CASC on 60 days' notice; the current third party supply contract has a term through August 31, 2016. Grundartangi Grundartangi has power purchase agreements with HS Orka hf ("HS"), Landsvirkjun and Orkuveita Reykjavikur ("OR") to provide power to its Grundartangi smelter. These power purchase agreements, which will expire on various dates from 2019 through 2036 (subject to extension), provide power at LME-based variable rates. Each power purchase agreement contains take-or-pay obligations with respect to a significant percentage of the total committed and available power under such agreement. Helguvik Nordural Helguvik ehf ("Helguvik") has power purchase agreements with HS and OR to provide power to the Helguvik project. These power purchase agreements provide power at LME-based variable rates and contain take-or-pay obligations with respect to a significant percentage of the total committed and available power under such agreements. The power purchase agreements contain certain conditions to HS’s and OR’s obligations. HS (with respect to all phases) and OR (with respect to all phases other than the first phase) have alleged that certain of these conditions have not been satisfied. The first stage of power under the OR power purchase agreement (approximately 47.5 MW) became available in the fourth quarter of 2011 and is currently being utilized at Grundartangi. In July 2014, HS commenced arbitration proceedings against Helguvik seeking, among other things, an order declaring, (i) that the conditions to the power contract have not been fulfilled and, (ii) that the power contract is therefore no longer valid. Helguvik believes HS' claims are without merit and intends to defend itself against them. Other Commitments and Contingencies Labor Commitments The bargaining unit employees at our Grundartangi, Vlissingen, Hawesville, Sebree and Ravenswood facilities are represented by labor unions, representing 63% of our total workforce. Approximately 84% of Grundartangi’s work force is represented by five labor unions, governed by a labor agreement which is effective through December 31, 2019 that establishes wages and work rules for covered employees. 100% of Vlissingen's work force is represented by the Federation for the Metal and Electrical Industry ("FME") which negotiates working conditions with trade unions on behalf of its members. In March 2016, a new labor agreement was reached with the FME which is effective retroactively from May 1, 2015 to June 1, 2018. Approximately 52% of our U.S. based work force is represented by the USW. In June 2015, CAKY entered into a new collective bargaining agreement with the USW for its employees at the Hawesville smelter. The agreement is effective through April 1, 2020. Century Sebree, LLC has a collective bargaining agreement with the USW for its employees at the Sebree smelter that is effective through October 28, 2019.

Components of accumulated other

Components of accumulated other comprehensive loss	3 Months Ended
	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Components of accumulated other comprehensive loss	Components of accumulated other comprehensive loss March 31, 2016 December 31, 2015 Defined benefit plan liabilities $ (120,658 ) $ (121,910 ) Unrealized loss on financial instruments (1,481 ) (1,435 ) Other comprehensive loss before income tax effect (122,139 ) (123,345 ) Income tax effect (1) 10,312 10,695 Accumulated other comprehensive loss $ (111,827 ) $ (112,650 ) (1) The allocation of the income tax effect to the components of other comprehensive income is as follows: March 31, 2016 December 31, 2015 Defined benefit plan liabilities $ 10,852 $ 11,243 Unrealized loss on financial instruments (540 ) (548 ) The following table summarizes the changes in the accumulated balances for each component of accumulated other comprehensive loss ("AOCL"): Defined benefit plan and other postretirement liabilities Unrealized loss on financial instruments Total, net of tax Balance, December 31, 2015 $ (110,667 ) $ (1,983 ) $ (112,650 ) Net amount reclassified to net loss 861 (38 ) 823 Balance, March 31, 2016 $ (109,806 ) $ (2,021 ) $ (111,827 ) Balance, December 31, 2014 $ (115,852 ) $ (1,830 ) $ (117,682 ) Net amount reclassified to net income 117 (39 ) 78 Balance, March 31, 2015 $ (115,735 ) $ (1,869 ) $ (117,604 ) Reclassifications out of AOCL were included in the consolidated statements of operations as follows: For the three months ended March 31 AOCL Components Location 2016 2015 Defined benefit plan and other postretirement liabilities Cost of goods sold $ 777 $ 325 Selling, general and administrative expenses 125 183 Other operating expense, net 350 — Income tax expense (391 ) (391 ) Net of tax $ 861 $ 117 Unrealized loss on financial instruments Cost of goods sold $ (46 ) $ (47 ) Income tax benefit 8 8 Net of tax $ (38 ) $ (39 )

Components of net periodic bene

Components of net periodic benefit cost	3 Months Ended
	Mar. 31, 2016
Components of net periodic benefit cost [Abstract]
Components of net periodic benefit cost	Components of net periodic benefit cost Pension Benefits Three months ended March 31, 2016 2015 Service cost $ 1,270 $ 1,704 Interest cost 3,480 3,388 Expected return on plan assets (4,816 ) (5,494 ) Amortization of prior service costs 28 25 Amortization of net loss 1,043 620 Net periodic benefit cost $ 1,005 $ 243 Other Postretirement Benefits ("OPEB") Three months ended March 31, 2016 2015 Service cost $ 330 $ 562 Interest cost 1,456 1,591 Amortization of prior service cost (695 ) (961 ) Amortization of net loss 876 865 Net periodic benefit cost $ 1,967 $ 2,057 Employer contributions During the three months ended March 31, 2016 , we made contributions of $464 to the qualified defined benefit and unqualified supplemental executive retirement benefits ("SERB") plans that we sponsor.

Restricted Cash

Restricted Cash	3 Months Ended
	Mar. 31, 2016
Cash and Cash Equivalents [Abstract]
Restricted Cash	Restricted cash In March 2015, we posted $21,000 cash collateral with EDF Trading North America, LLC ("EDF") for the annual Midcontinent Independent System Operator ("MISO") power capacity auction and recorded restricted cash deposits for the three months ended March 31, 2015. In April 2015, EDF released our $21,000 cash collateral because it was no longer required based on the final MISO auction clearing price.

Supplemental cash flow informat

Supplemental cash flow information	3 Months Ended
	Mar. 31, 2016
Supplemental Cash Flow Elements [Abstract]
Supplemental cash flow information	Supplemental cash flow information Three months ended March 31, 2016 2015 Cash paid for: Interest $ 160 $ 5 Income taxes 2,596 1,142 Non-cash investing activities: Accrued capital costs $ 206 $ 1,202

Condensed consolidating financi

Condensed consolidating financial information	3 Months Ended
	Mar. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed consolidating financial information	Condensed consolidating financial information Our 2021 Notes are guaranteed by each of our material existing and future domestic subsidiaries, except for Nordural US LLC and Century Aluminum Development LLC. The Guarantor Subsidiaries are 100% owned by Century. All guarantees are full and unconditional; all guarantees are joint and several. These notes are not guaranteed by our foreign subsidiaries (such foreign subsidiaries, Nordural US LLC and Century Aluminum Development LLC, collectively the “Non-Guarantor Subsidiaries”). We allocate corporate expenses or income to our subsidiaries and charge interest on certain intercompany balances. The following summarized condensed consolidating statements of comprehensive income (loss) for the three months ended March 31, 2016 and 2015, condensed consolidating balance sheets as of March 31, 2016 and December 31, 2015 and the condensed consolidating statements of cash flows for the three months ended March 31, 2016 and 2015 present separate results for Century, the Guarantor Subsidiaries, the Non-Guarantor Subsidiaries, consolidating adjustments and total consolidated amounts. Although Century Aluminum West Virginia (which owns our curtailed Ravenswood smelter) has guaranteed our Notes due 2021, because we are in the process of selling substantially all of its assets, we have included its assets and results of operations in the columns under the caption Non-Guarantor Subsidiaries. Condensed Consolidating Statements of Comprehensive Income (Loss) For the three months ended March 31, 2016 The Company Combined Guarantor Subsidiaries Combined Non-Guarantor Subsidiaries Consolidating Adjustments Total Consolidated NET SALES: Related parties $ — $ 162,120 $ 141,654 $ (23,397 ) $ 280,377 Third-party customers — 38,468 9 — 38,477 Total net sales — 200,588 141,663 (23,397 ) 318,854 Cost of goods sold — 209,573 136,304 (23,971 ) 321,906 Gross profit (loss) — (8,985 ) 5,359 574 (3,052 ) Selling, general and administrative expenses 8,299 — 1,326 — 9,625 Other operating expense - net — — 881 — 881 Operating income (loss) (8,299 ) (8,985 ) 3,152 574 (13,558 ) Interest expense - third parties (5,065 ) (382 ) (46 ) — (5,493 ) Interest income (expense) - affiliates 9,548 — (9,548 ) — — Interest income - third parties 37 — 77 — 114 Net gain on forward and derivative contracts — 353 — — 353 Other income (expense) - net 771 (6 ) (771 ) — (6 ) Loss before income taxes and equity in earnings (loss) of joint ventures (3,008 ) (9,020 ) (7,136 ) 574 (18,590 ) Income tax benefit 620 — 1,450 — 2,070 Loss before income taxes and equity in earnings (loss) of joint ventures (2,388 ) (9,020 ) (5,686 ) 574 (16,520 ) Equity in earnings (loss) of joint ventures (13,775 ) — 357 13,775 357 Net loss $ (16,163 ) $ (9,020 ) $ (5,329 ) $ 14,349 $ (16,163 ) Other comprehensive income before income tax effect 1,206 778 303 (1,081 ) 1,206 Income tax effect (383 ) — 8 (8 ) (383 ) Other comprehensive income (loss) 823 778 311 (1,089 ) 823 Total comprehensive loss $ (15,340 ) $ (8,242 ) $ (5,018 ) $ 13,260 $ (15,340 ) Condensed Consolidating Statements of Comprehensive Income (Loss) For the three months ended March 31, 2015 The Company Combined Guarantor Subsidiaries Combined Non-Guarantor Subsidiaries Consolidating Adjustments Total Consolidated NET SALES: Related parties $ — $ 403,064 $ 173,779 $ (1,114 ) $ 575,729 Third-party customers — 12,874 6 (698 ) 12,182 Total net sales — 415,938 173,785 (1,812 ) 587,911 Cost of goods sold — 362,302 136,028 (4,514 ) 493,816 Gross profit — 53,636 37,757 2,702 94,095 Selling, general and administrative expenses 10,837 (944 ) 1,078 1,000 11,971 Other operating expense - net — — 2,079 — 2,079 Operating income (loss) (10,837 ) 54,580 34,600 1,702 80,045 Interest expense - third parties (5,109 ) (396 ) (46 ) — (5,551 ) Interest income (expense) - affiliates 10,226 — (10,226 ) — — Interest income - third parties 15 4 123 — 142 Net gain on forward and derivative contracts — 353 — — 353 Unrealized gain on fair value of contingent consideration — 6,527 — — 6,527 Other income (expense) - net 537 (484 ) 2,731 (1,730 ) 1,054 Income (loss) before income taxes and equity in earnings of joint ventures (5,168 ) 60,584 27,182 (28 ) 82,570 Income tax expense (299 ) — (9,052 ) 50 (9,301 ) Income (loss) before equity in earnings of joint ventures (5,467 ) 60,584 18,130 22 73,269 Equity in earnings of joint ventures 79,246 — 510 (79,246 ) 510 Net income $ 73,779 $ 60,584 $ 18,640 $ (79,224 ) $ 73,779 Other comprehensive income before income tax effect 461 33 245 (278 ) 461 Income tax effect (383 ) — 8 (8 ) (383 ) Other comprehensive income (loss) 78 33 253 (286 ) 78 Total comprehensive income $ 73,857 $ 60,617 $ 18,893 $ (79,510 ) $ 73,857 Condensed Consolidating Balance Sheet As of March 31, 2016 The Company Combined Guarantor Subsidiaries Combined Non-Guarantor Subsidiaries Consolidating Adjustments Total Consolidated Cash & cash equivalents $ 49,667 $ (74 ) $ 76,868 $ — $ 126,461 Restricted cash — 795 — — 795 Accounts receivable - net — 12,088 580 — 12,668 Due from affiliates 382 13,955 1,141 — 15,478 Inventories 180 142,070 80,526 (2,274 ) 220,502 Prepaid and other current assets 7,073 4,290 18,259 — 29,622 Assets held for sale — — 29,715 — 29,715 Total current assets 57,302 173,124 207,089 (2,274 ) 435,241 Property, plant and equipment - net 8,863 352,384 853,975 — 1,215,222 Investment in subsidiaries 580,999 — — (580,999 ) — Due from affiliates - less current portion 639,780 — — (639,780 ) — Other assets 30,025 19,328 16,371 7,418 73,142 TOTAL $ 1,316,969 $ 544,836 $ 1,077,435 $ (1,215,635 ) $ 1,723,605 Accounts payable, trade $ 2,582 $ 47,777 $ 34,228 $ — $ 84,587 Due to affiliates 1,500 1,210 547 2,916 6,173 Accrued and other current liabilities 14,280 11,073 24,816 — 50,169 Accrued employee benefits costs 1,824 7,550 680 — 10,054 Industrial revenue bonds — 7,815 — — 7,815 Total current liabilities 20,186 75,425 60,271 2,916 158,798 Senior notes payable 247,380 — — — 247,380 Accrued pension benefits costs cost - less current portion 39,552 (11,009 ) 14,894 — 43,437 Accrued postretirement benefits costs - less current portion 4,834 119,529 1,578 — 125,941 Other liabilities 1,893 30,749 11,739 7,418 51,799 Intercompany loan — 126,343 518,353 (644,696 ) — Deferred taxes — — 93,399 — 93,399 Total noncurrent liabilities 293,659 265,612 639,963 (637,278 ) 561,956 Series A Preferred stock 1 — — — 1 Common stock 942 — 228,424 (228,424 ) 942 Additional paid-in capital 2,513,952 191,023 2,182,533 (2,373,556 ) 2,513,952 Treasury stock, at cost (86,276 ) — — — (86,276 ) Accumulated other comprehensive loss (13,391 ) (59,249 ) (39,187 ) — (111,827 ) Accumulated deficit (1,412,104 ) 72,025 (1,994,569 ) 2,020,707 (1,313,941 ) Total shareholder's equity 1,003,124 203,799 377,201 (581,273 ) 1,002,851 TOTAL $ 1,316,969 $ 544,836 $ 1,077,435 $ (1,215,635 ) $ 1,723,605 Condensed Consolidating Balance Sheet As of December 31, 2015 The Company Combined Guarantor Subsidiaries Combined Non-Guarantor Subsidiaries Consolidating Adjustments Total Consolidated Cash & cash equivalents $ 58,421 $ (3,647 ) $ 60,619 $ — $ 115,393 Restricted cash — 791 — — 791 Accounts receivable - net 104 8,891 480 — 9,475 Due from affiliates 13 14,493 2,911 — 17,417 Inventories 180 148,280 85,937 (2,525 ) 231,872 Prepaid and other current assets 7,713 16,242 18,457 — 42,412 Assets held for sale — — 30,697 — 30,697 Total current assets 66,431 185,050 199,101 (2,525 ) 448,057 Property, plant and equipment - net 9,188 361,626 861,442 — 1,232,256 Investment in subsidiaries 593,604 — — (593,604 ) — Due from affiliates - less current portion 632,170 — — (632,170 ) — Other assets 29,536 19,153 16,047 7,419 72,155 TOTAL $ 1,330,929 $ 565,829 $ 1,076,590 $ (1,220,880 ) $ 1,752,468 Accounts payable, trade $ 2,380 $ 53,145 $ 34,964 $ — $ 90,489 Due to affiliates 2,143 7,167 735 — 10,045 Accrued and other current liabilities 11,247 14,759 22,816 — 48,822 Accrued employee benefits costs 1,824 7,644 680 — 10,148 Industrial revenue bonds — 7,815 — — 7,815 Total current liabilities 17,594 90,530 59,195 — 167,319 Senior notes payable 247,278 — — — 247,278 Accrued pension benefits costs cost - less current portion 39,831 (11,021 ) 15,189 — 43,999 Accrued postretirement benefits costs - less current portion 4,524 119,911 1,564 — 125,999 Other liabilities 3,307 30,505 11,779 7,418 53,009 Intercompany loan — 124,518 509,652 (634,170 ) — Deferred taxes — — 96,994 — 96,994 Total noncurrent liabilities 294,940 263,913 635,178 (626,752 ) 567,279 Series A Preferred stock 1 — — — 1 Common stock 942 — 224,424 (224,424 ) 942 Additional paid-in capital 2,513,631 191,023 2,038,138 (2,229,161 ) 2,513,631 Treasury stock, at cost (86,276 ) — — — (86,276 ) Accumulated other comprehensive loss (13,125 ) (60,026 ) (39,499 ) — (112,650 ) Accumulated deficit (1,396,778 ) 80,389 (1,840,846 ) 1,859,457 (1,297,778 ) Total shareholder's equity 1,018,395 211,386 382,217 (594,128 ) 1,017,870 TOTAL $ 1,330,929 $ 565,829 $ 1,076,590 $ (1,220,880 ) $ 1,752,468 Condensed Consolidating Statement of Cash Flows For the three months ended March 31, 2016 The Company Combined Guarantor Subsidiaries Combined Non-Guarantor Subsidiaries Consolidating Adjustments Total Consolidated Net cash provided by (used in) operating activities $ (8,754 ) $ 5,435 $ 9,956 $ 8,266 $ 14,903 Purchase of property, plant and equipment — (1,426 ) (2,409 ) — (3,835 ) Net cash used in investing activities — (1,426 ) (2,409 ) — (3,835 ) Borrowings under revolving credit facilities 371 — — — 371 Repayments under revolving credit facilities (371 ) — — — (371 ) Intercompany transactions — (436 ) 8,702 (8,266 ) — Net cash provided by (used in) financing activities — (436 ) 8,702 (8,266 ) — CHANGE IN CASH AND CASH EQUIVALENTS (8,754 ) 3,573 16,249 — 11,068 Cash and cash equivalents, beginning of period 58,421 (3,647 ) 60,619 — 115,393 Cash and cash equivalents, end of period $ 49,667 $ (74 ) $ 76,868 $ — $ 126,461 Condensed Consolidating Statement of Cash Flows For the three months ended March 31, 2015 The Company Combined Guarantor Subsidiaries Combined Non-Guarantor Subsidiaries Consolidating Adjustments Total Consolidated Net cash provided by (used in) operating activities $ 113,179 $ 40,025 $ (222,561 ) $ 185,624 $ 116,267 Purchase of property, plant and equipment (348 ) (6,726 ) (5,553 ) — (12,627 ) Restricted and other cash deposits — (21,012 ) — — (21,012 ) Net cash used in investing activities (348 ) (27,738 ) (5,553 ) — (33,639 ) Borrowings under revolving credit facilities 455 — — — 455 Repayments under revolving credit facilities (455 ) — — — (455 ) Repurchase of common stock (19,439 ) — — — (19,439 ) Intercompany transactions — (11,164 ) 196,788 (185,624 ) — Net cash provided by (used in) financing activities (19,439 ) (11,164 ) 196,788 (185,624 ) (19,439 ) CHANGE IN CASH AND CASH EQUIVALENTS 93,392 1,123 (31,326 ) — 63,189 Cash and cash equivalents, beginning of period 70,683 (1,187 ) 93,746 — 163,242 Cash and cash equivalents, end of period $ 164,075 $ (64 ) $ 62,420 $ — $ 226,431

Fair value measurements (Polici

Fair value measurements (Policies)	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Transfer, Policy	It is our policy to recognize transfers into and transfers out of Level 3 as of the date of the event or change in circumstances that caused the transfer.

Related party transactions (Tab

Related party transactions (Tables)	3 Months Ended
	Mar. 31, 2016
Related Party Transactions [Abstract]
Schedule of related party transactions	A summary of the aforementioned significant related party transactions for the three months ended March 31, 2016 and 2015 is as follows: Three months ended March 31, 2016 2015 Net sales to Glencore $ 280,377 $ 575,729 Purchases from Glencore 44,013 107,814 Purchases from BHH 2,383 14,820

Business acquisitions (Tables)

Business acquisitions (Tables)	3 Months Ended
	Mar. 31, 2016
Business Combinations [Abstract]
Summary of consideration transferred	The following table summarizes all of the elements of purchase consideration for the transaction as of December 1, 2014. Purchase price $ 67,500 Contingent consideration 13,780 Economic, working capital and other closing adjustments (13,513 ) Total consideration $ 67,767

Fair value measurements (Tables

Fair value measurements (Tables)	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Schedule of valuation methodology for assets and liabilities at fair value	The following section describes the valuation methodology used to measure our financial assets and liabilities that were accounted for at fair value and are categorized based on the fair value hierarchy described in Accounting Standards Codification ("ASC") 820, "Fair Value Measurements and Disclosures." Overview of Century’s valuation methodology Level Significant inputs Cash equivalents 1 Quoted market prices Trust assets (1) 1 Quoted market prices Surety bonds 1 Quoted market prices E.ON contingent obligation 3 Quoted LME forward market, management’s estimates of the LME forward market prices for periods beyond the quoted periods and management’s estimate of future level of operations (1) Trust assets are currently invested in money market funds. These trust assets are held to fund the non-qualified supplemental executive pension benefit obligations for certain of our officers. The trust has sole authority to invest the funds in secure interest producing investments consisting of short-term securities issued or guaranteed by the United States government or cash and cash equivalents.
Financial assets and liabilities at fair value on a recurring basis	The following table sets forth our financial assets and liabilities that were accounted for at fair value on a recurring basis by the level of input within the ASC 820 fair value hierarchy. Recurring Fair Value Measurements As of March 31, 2016 Level 1 Level 2 Level 3 Total ASSETS: Cash equivalents $ 120,061 $ — $ — $ 120,061 Trust assets 4,789 — — 4,789 Surety bonds 1,870 — — 1,870 TOTAL $ 126,720 $ — $ — $ 126,720 LIABILITIES: E.ON contingent obligation - net $ — $ — $ — $ — TOTAL $ — $ — $ — $ — Recurring Fair Value Measurements As of December 31, 2015 Level 1 Level 2 Level 3 Total ASSETS: Cash equivalents $ 102,675 $ — $ — $ 102,675 Trust assets 5,226 — — 5,226 Surety bonds 1,870 — — 1,870 TOTAL $ 109,771 $ — $ — $ 109,771 LIABILITIES: E.ON contingent obligation – net $ — $ — $ — $ — TOTAL $ — $ — $ — $ —

Earnings (loss) per share (Tabl

Earnings (loss) per share (Tables)	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Basic and diluted earnings (loss) per share	The following table shows the basic and diluted earnings (loss) per share for the three months ended March 31, 2016 and 2015 : For the three months ended March 31, 2016 2015 Loss Shares (000) Per-Share Income Shares (000) Per-Share Net income (loss) $ (16,163 ) $ 73,779 Amount allocated to common stockholders 100.00 % 91.91 % Basic EPS: Net income (loss) allocated to common stockholders (16,163 ) 87,040 $ (0.19 ) 67,813 88,814 $ 0.76 Effect of Dilutive Securities: Share-based compensation plans — — — 555 Diluted EPS: Net income (loss) allocated to common stockholders $ (16,163 ) 87,040 $ (0.19 ) $ 67,813 89,369 $ 0.76
Securities excluded from the calculation of diluted EPS	Securities excluded from the calculation of diluted EPS: Three months ended March 31, 2016 2015 Stock options (1) 393,237 333,266 Service-based share awards (1) 498,809 — (1) In periods when we report a net loss, all share awards are excluded from the calculation of diluted weighted average shares outstanding because of their antidilutive effect on earnings (loss) per share. In periods when we report net income, certain option awards may be excluded from the calculation of diluted EPS if the exercise price of the option award was greater than the average market price of the underlying common stock.

Shareholders' equity (Tables)

Shareholders' equity (Tables)	3 Months Ended
	Mar. 31, 2016
Stockholders' Equity Note [Abstract]
Common and Preferred Stock Activity	The Common and Preferred Stock Activity table below contains additional information about preferred stock conversions during the three months ended March 31, 2016 and 2015 . Common and Preferred Stock Activity: Preferred stock Common stock (in shares) Series A convertible Treasury Outstanding Beginning balance as of December 31, 2015 76,539 7,186,521 87,038,050 Repurchase of common stock — — — Conversion of convertible preferred stock (93 ) — 9,305 Issuance for share-based compensation plans — — 12,378 Ending balance as of March 31, 2016 76,446 7,186,521 87,059,733 Beginning balance as of December 31, 2014 78,141 4,786,521 89,064,582 Repurchase of common stock — 1,200,000 (1,200,000 ) Conversion of convertible preferred stock (80 ) — 7,947 Issuance for share-based compensation plans — — 10,828 Ending balance as of March 31, 2015 78,061 5,986,521 87,883,357

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2016
Inventory, Net [Abstract]
Schedule of Inventories	Inventories consist of the following: March 31, 2016 December 31, 2015 Raw materials $ 54,914 $ 52,121 Work-in-process 28,302 34,025 Finished goods 18,821 15,988 Operating and other supplies 118,465 129,738 Total inventories $ 220,502 $ 231,872

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Schedule of Debt	March 31, 2016 December 31, 2015 Debt classified as current liabilities: Hancock County industrial revenue bonds ("IRBs") due 2028, interest payable quarterly (variable interest rates (not to exceed 12%)) (1) $ 7,815 $ 7,815 Debt classified as non-current liabilities: 7.5% senior secured notes due June 1, 2021, net of debt discount of $2,620 and $2,722, respectively, interest payable semiannually 247,380 247,278 Total $ 255,195 $ 255,093 (1) The IRBs are classified as current liabilities because they are remarketed weekly and could be required to be repaid upon demand if there is a failed remarketing. The IRB interest rate at March 31, 2016 was 0.59% .
Schedule of Line of Credit Facilities	Status of our Iceland revolving credit facility: March 31, 2016 Credit facility maximum amount $ 50,000 Borrowing availability 45,397 Outstanding borrowings — Borrowing availability, net of borrowings 45,397 Status of our U.S. revolving credit facility: March 31, 2016 Credit facility maximum amount $ 150,000 Borrowing availability 85,844 Outstanding letters of credit issued 44,759 Outstanding borrowings — Borrowing availability, net of outstanding letters of credit and borrowings 41,085

Components of accumulated oth29

Components of accumulated other comprehensive loss (Tables)	3 Months Ended
	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated balances for each component of AOCI	The following table summarizes the changes in the accumulated balances for each component of accumulated other comprehensive loss ("AOCL"): Defined benefit plan and other postretirement liabilities Unrealized loss on financial instruments Total, net of tax Balance, December 31, 2015 $ (110,667 ) $ (1,983 ) $ (112,650 ) Net amount reclassified to net loss 861 (38 ) 823 Balance, March 31, 2016 $ (109,806 ) $ (2,021 ) $ (111,827 ) Balance, December 31, 2014 $ (115,852 ) $ (1,830 ) $ (117,682 ) Net amount reclassified to net income 117 (39 ) 78 Balance, March 31, 2015 $ (115,735 ) $ (1,869 ) $ (117,604 ) March 31, 2016 December 31, 2015 Defined benefit plan liabilities $ (120,658 ) $ (121,910 ) Unrealized loss on financial instruments (1,481 ) (1,435 ) Other comprehensive loss before income tax effect (122,139 ) (123,345 ) Income tax effect (1) 10,312 10,695 Accumulated other comprehensive loss $ (111,827 ) $ (112,650 ) (1) The allocation of the income tax effect to the components of other comprehensive income is as follows: March 31, 2016 December 31, 2015 Defined benefit plan liabilities $ 10,852 $ 11,243 Unrealized loss on financial instruments (540 ) (548 )
Reclassification out of AOCI	Reclassifications out of AOCL were included in the consolidated statements of operations as follows: For the three months ended March 31 AOCL Components Location 2016 2015 Defined benefit plan and other postretirement liabilities Cost of goods sold $ 777 $ 325 Selling, general and administrative expenses 125 183 Other operating expense, net 350 — Income tax expense (391 ) (391 ) Net of tax $ 861 $ 117 Unrealized loss on financial instruments Cost of goods sold $ (46 ) $ (47 ) Income tax benefit 8 8 Net of tax $ (38 ) $ (39 )

Components of net periodic be30

Components of net periodic benefit cost (Tables)	3 Months Ended
	Mar. 31, 2016
Components of net periodic benefit cost [Abstract]
Schedule of net periodic benefit cost	Pension Benefits Three months ended March 31, 2016 2015 Service cost $ 1,270 $ 1,704 Interest cost 3,480 3,388 Expected return on plan assets (4,816 ) (5,494 ) Amortization of prior service costs 28 25 Amortization of net loss 1,043 620 Net periodic benefit cost $ 1,005 $ 243 Other Postretirement Benefits ("OPEB") Three months ended March 31, 2016 2015 Service cost $ 330 $ 562 Interest cost 1,456 1,591 Amortization of prior service cost (695 ) (961 ) Amortization of net loss 876 865 Net periodic benefit cost $ 1,967 $ 2,057

Supplemental cash flow inform31

Supplemental cash flow information (Tables)	3 Months Ended
	Mar. 31, 2016
Supplemental Cash Flow Elements [Abstract]
Supplemental cash flow information	Three months ended March 31, 2016 2015 Cash paid for: Interest $ 160 $ 5 Income taxes 2,596 1,142 Non-cash investing activities: Accrued capital costs $ 206 $ 1,202

Condensed consolidating finan32

Condensed consolidating financial information (Tables)	3 Months Ended
	Mar. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Consolidating Statements of Comprehensive Income (Loss)	Condensed Consolidating Statements of Comprehensive Income (Loss) For the three months ended March 31, 2016 The Company Combined Guarantor Subsidiaries Combined Non-Guarantor Subsidiaries Consolidating Adjustments Total Consolidated NET SALES: Related parties $ — $ 162,120 $ 141,654 $ (23,397 ) $ 280,377 Third-party customers — 38,468 9 — 38,477 Total net sales — 200,588 141,663 (23,397 ) 318,854 Cost of goods sold — 209,573 136,304 (23,971 ) 321,906 Gross profit (loss) — (8,985 ) 5,359 574 (3,052 ) Selling, general and administrative expenses 8,299 — 1,326 — 9,625 Other operating expense - net — — 881 — 881 Operating income (loss) (8,299 ) (8,985 ) 3,152 574 (13,558 ) Interest expense - third parties (5,065 ) (382 ) (46 ) — (5,493 ) Interest income (expense) - affiliates 9,548 — (9,548 ) — — Interest income - third parties 37 — 77 — 114 Net gain on forward and derivative contracts — 353 — — 353 Other income (expense) - net 771 (6 ) (771 ) — (6 ) Loss before income taxes and equity in earnings (loss) of joint ventures (3,008 ) (9,020 ) (7,136 ) 574 (18,590 ) Income tax benefit 620 — 1,450 — 2,070 Loss before income taxes and equity in earnings (loss) of joint ventures (2,388 ) (9,020 ) (5,686 ) 574 (16,520 ) Equity in earnings (loss) of joint ventures (13,775 ) — 357 13,775 357 Net loss $ (16,163 ) $ (9,020 ) $ (5,329 ) $ 14,349 $ (16,163 ) Other comprehensive income before income tax effect 1,206 778 303 (1,081 ) 1,206 Income tax effect (383 ) — 8 (8 ) (383 ) Other comprehensive income (loss) 823 778 311 (1,089 ) 823 Total comprehensive loss $ (15,340 ) $ (8,242 ) $ (5,018 ) $ 13,260 $ (15,340 ) Condensed Consolidating Statements of Comprehensive Income (Loss) For the three months ended March 31, 2015 The Company Combined Guarantor Subsidiaries Combined Non-Guarantor Subsidiaries Consolidating Adjustments Total Consolidated NET SALES: Related parties $ — $ 403,064 $ 173,779 $ (1,114 ) $ 575,729 Third-party customers — 12,874 6 (698 ) 12,182 Total net sales — 415,938 173,785 (1,812 ) 587,911 Cost of goods sold — 362,302 136,028 (4,514 ) 493,816 Gross profit — 53,636 37,757 2,702 94,095 Selling, general and administrative expenses 10,837 (944 ) 1,078 1,000 11,971 Other operating expense - net — — 2,079 — 2,079 Operating income (loss) (10,837 ) 54,580 34,600 1,702 80,045 Interest expense - third parties (5,109 ) (396 ) (46 ) — (5,551 ) Interest income (expense) - affiliates 10,226 — (10,226 ) — — Interest income - third parties 15 4 123 — 142 Net gain on forward and derivative contracts — 353 — — 353 Unrealized gain on fair value of contingent consideration — 6,527 — — 6,527 Other income (expense) - net 537 (484 ) 2,731 (1,730 ) 1,054 Income (loss) before income taxes and equity in earnings of joint ventures (5,168 ) 60,584 27,182 (28 ) 82,570 Income tax expense (299 ) — (9,052 ) 50 (9,301 ) Income (loss) before equity in earnings of joint ventures (5,467 ) 60,584 18,130 22 73,269 Equity in earnings of joint ventures 79,246 — 510 (79,246 ) 510 Net income $ 73,779 $ 60,584 $ 18,640 $ (79,224 ) $ 73,779 Other comprehensive income before income tax effect 461 33 245 (278 ) 461 Income tax effect (383 ) — 8 (8 ) (383 ) Other comprehensive income (loss) 78 33 253 (286 ) 78 Total comprehensive income $ 73,857 $ 60,617 $ 18,893 $ (79,510 ) $ 73,857
Condensed Consolidating Balance Sheet	Condensed Consolidating Balance Sheet As of March 31, 2016 The Company Combined Guarantor Subsidiaries Combined Non-Guarantor Subsidiaries Consolidating Adjustments Total Consolidated Cash & cash equivalents $ 49,667 $ (74 ) $ 76,868 $ — $ 126,461 Restricted cash — 795 — — 795 Accounts receivable - net — 12,088 580 — 12,668 Due from affiliates 382 13,955 1,141 — 15,478 Inventories 180 142,070 80,526 (2,274 ) 220,502 Prepaid and other current assets 7,073 4,290 18,259 — 29,622 Assets held for sale — — 29,715 — 29,715 Total current assets 57,302 173,124 207,089 (2,274 ) 435,241 Property, plant and equipment - net 8,863 352,384 853,975 — 1,215,222 Investment in subsidiaries 580,999 — — (580,999 ) — Due from affiliates - less current portion 639,780 — — (639,780 ) — Other assets 30,025 19,328 16,371 7,418 73,142 TOTAL $ 1,316,969 $ 544,836 $ 1,077,435 $ (1,215,635 ) $ 1,723,605 Accounts payable, trade $ 2,582 $ 47,777 $ 34,228 $ — $ 84,587 Due to affiliates 1,500 1,210 547 2,916 6,173 Accrued and other current liabilities 14,280 11,073 24,816 — 50,169 Accrued employee benefits costs 1,824 7,550 680 — 10,054 Industrial revenue bonds — 7,815 — — 7,815 Total current liabilities 20,186 75,425 60,271 2,916 158,798 Senior notes payable 247,380 — — — 247,380 Accrued pension benefits costs cost - less current portion 39,552 (11,009 ) 14,894 — 43,437 Accrued postretirement benefits costs - less current portion 4,834 119,529 1,578 — 125,941 Other liabilities 1,893 30,749 11,739 7,418 51,799 Intercompany loan — 126,343 518,353 (644,696 ) — Deferred taxes — — 93,399 — 93,399 Total noncurrent liabilities 293,659 265,612 639,963 (637,278 ) 561,956 Series A Preferred stock 1 — — — 1 Common stock 942 — 228,424 (228,424 ) 942 Additional paid-in capital 2,513,952 191,023 2,182,533 (2,373,556 ) 2,513,952 Treasury stock, at cost (86,276 ) — — — (86,276 ) Accumulated other comprehensive loss (13,391 ) (59,249 ) (39,187 ) — (111,827 ) Accumulated deficit (1,412,104 ) 72,025 (1,994,569 ) 2,020,707 (1,313,941 ) Total shareholder's equity 1,003,124 203,799 377,201 (581,273 ) 1,002,851 TOTAL $ 1,316,969 $ 544,836 $ 1,077,435 $ (1,215,635 ) $ 1,723,605 Condensed Consolidating Balance Sheet As of December 31, 2015 The Company Combined Guarantor Subsidiaries Combined Non-Guarantor Subsidiaries Consolidating Adjustments Total Consolidated Cash & cash equivalents $ 58,421 $ (3,647 ) $ 60,619 $ — $ 115,393 Restricted cash — 791 — — 791 Accounts receivable - net 104 8,891 480 — 9,475 Due from affiliates 13 14,493 2,911 — 17,417 Inventories 180 148,280 85,937 (2,525 ) 231,872 Prepaid and other current assets 7,713 16,242 18,457 — 42,412 Assets held for sale — — 30,697 — 30,697 Total current assets 66,431 185,050 199,101 (2,525 ) 448,057 Property, plant and equipment - net 9,188 361,626 861,442 — 1,232,256 Investment in subsidiaries 593,604 — — (593,604 ) — Due from affiliates - less current portion 632,170 — — (632,170 ) — Other assets 29,536 19,153 16,047 7,419 72,155 TOTAL $ 1,330,929 $ 565,829 $ 1,076,590 $ (1,220,880 ) $ 1,752,468 Accounts payable, trade $ 2,380 $ 53,145 $ 34,964 $ — $ 90,489 Due to affiliates 2,143 7,167 735 — 10,045 Accrued and other current liabilities 11,247 14,759 22,816 — 48,822 Accrued employee benefits costs 1,824 7,644 680 — 10,148 Industrial revenue bonds — 7,815 — — 7,815 Total current liabilities 17,594 90,530 59,195 — 167,319 Senior notes payable 247,278 — — — 247,278 Accrued pension benefits costs cost - less current portion 39,831 (11,021 ) 15,189 — 43,999 Accrued postretirement benefits costs - less current portion 4,524 119,911 1,564 — 125,999 Other liabilities 3,307 30,505 11,779 7,418 53,009 Intercompany loan — 124,518 509,652 (634,170 ) — Deferred taxes — — 96,994 — 96,994 Total noncurrent liabilities 294,940 263,913 635,178 (626,752 ) 567,279 Series A Preferred stock 1 — — — 1 Common stock 942 — 224,424 (224,424 ) 942 Additional paid-in capital 2,513,631 191,023 2,038,138 (2,229,161 ) 2,513,631 Treasury stock, at cost (86,276 ) — — — (86,276 ) Accumulated other comprehensive loss (13,125 ) (60,026 ) (39,499 ) — (112,650 ) Accumulated deficit (1,396,778 ) 80,389 (1,840,846 ) 1,859,457 (1,297,778 ) Total shareholder's equity 1,018,395 211,386 382,217 (594,128 ) 1,017,870 TOTAL $ 1,330,929 $ 565,829 $ 1,076,590 $ (1,220,880 ) $ 1,752,468
Condensed Consolidating Statement of Cash Flows	Condensed Consolidating Statement of Cash Flows For the three months ended March 31, 2016 The Company Combined Guarantor Subsidiaries Combined Non-Guarantor Subsidiaries Consolidating Adjustments Total Consolidated Net cash provided by (used in) operating activities $ (8,754 ) $ 5,435 $ 9,956 $ 8,266 $ 14,903 Purchase of property, plant and equipment — (1,426 ) (2,409 ) — (3,835 ) Net cash used in investing activities — (1,426 ) (2,409 ) — (3,835 ) Borrowings under revolving credit facilities 371 — — — 371 Repayments under revolving credit facilities (371 ) — — — (371 ) Intercompany transactions — (436 ) 8,702 (8,266 ) — Net cash provided by (used in) financing activities — (436 ) 8,702 (8,266 ) — CHANGE IN CASH AND CASH EQUIVALENTS (8,754 ) 3,573 16,249 — 11,068 Cash and cash equivalents, beginning of period 58,421 (3,647 ) 60,619 — 115,393 Cash and cash equivalents, end of period $ 49,667 $ (74 ) $ 76,868 $ — $ 126,461 Condensed Consolidating Statement of Cash Flows For the three months ended March 31, 2015 The Company Combined Guarantor Subsidiaries Combined Non-Guarantor Subsidiaries Consolidating Adjustments Total Consolidated Net cash provided by (used in) operating activities $ 113,179 $ 40,025 $ (222,561 ) $ 185,624 $ 116,267 Purchase of property, plant and equipment (348 ) (6,726 ) (5,553 ) — (12,627 ) Restricted and other cash deposits — (21,012 ) — — (21,012 ) Net cash used in investing activities (348 ) (27,738 ) (5,553 ) — (33,639 ) Borrowings under revolving credit facilities 455 — — — 455 Repayments under revolving credit facilities (455 ) — — — (455 ) Repurchase of common stock (19,439 ) — — — (19,439 ) Intercompany transactions — (11,164 ) 196,788 (185,624 ) — Net cash provided by (used in) financing activities (19,439 ) (11,164 ) 196,788 (185,624 ) (19,439 ) CHANGE IN CASH AND CASH EQUIVALENTS 93,392 1,123 (31,326 ) — 63,189 Cash and cash equivalents, beginning of period 70,683 (1,187 ) 93,746 — 163,242 Cash and cash equivalents, end of period $ 164,075 $ (64 ) $ 62,420 $ — $ 226,431

Related party transactions - Su

Related party transactions - Summary of related party transactions (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Related Party Transaction [Line Items]
Net sales to Glencore	$ 280,377	$ 575,729
Glencore [Member]
Related Party Transaction [Line Items]
Net sales to Glencore	280,377	575,729
Purchases from Glencore	44,013	107,814
BHH [Member]
Related Party Transaction [Line Items]
Purchases from BHH	$ 2,383	$ 14,820

Related party transactions - Na

Related party transactions - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016t	Dec. 31, 2015USD ($)
Glencore [Member]
Related Party Transaction [Line Items]
Ownership percentage by majority shareholder	47.50%
BHH [Member]
Related Party Transaction [Line Items]
Ownership percentage	40.00%
Impairment of equity method investment | $		$ 11,584
Agreement to Sell Molten Aluminum [Member] | Affiliated Entity [Member]
Related Party Transaction [Line Items]
Sales agreement, amount of agreement (tonnes) | t	24,500
Common Stock [Member] | Glencore [Member]
Related Party Transaction [Line Items]
Ownership percentage by majority shareholder	42.90%

Business acquisitions - Acquisi

Business acquisitions - Acquisition of Mt. Holly smelter narrative other units (Details) t in Thousands	Dec. 01, 2014employeet	Nov. 30, 2014
Mt. Holly Smelter [Member]
Business Acquisition [Line Items]
Remaining percentage acquired in step acquisition		50.30%
Percentage of ownership after step acquisition	100.00%
Employees | employee	600
Mt Holly primary aluminum capacity (tonnes) | t	231
Mt. Holly [Member] | Berkeley Aluminum Inc. [Member]
Business Acquisition [Line Items]
Ownership percentage		49.70%

Business acquisitions - Summary

Business acquisitions - Summary of consideration transferred (Details) - Mt. Holly Smelter [Member] $ in Thousands	Dec. 01, 2014USD ($)
Business Acquisition [Line Items]
Purchase price	$ 67,500
Contingent consideration	13,780
Economic, working capital and other closing adjustments	(13,513)
Total consideration	$ 67,767

Business acquisitions - Acqui37

Business acquisitions - Acquisition of Mt. Holly smelter narrative (Details) - USD ($) $ in Thousands	Dec. 01, 2014	Mar. 31, 2016	Apr. 30, 2015	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Unrealized gain on fair value of contingent consideration				$ 0	$ 6,527
Total net cash consideration paid	$ 41,487
Mt. Holly Smelter [Member]
Business Acquisition [Line Items]
Purchase price	67,500
Acquisition costs	1,539
Contingent consideration at acquisition date	13,780
Unrealized gain on fair value of contingent consideration				$ 6,527		$ 18,337	$ 7,943
Proceeds from acquisition - contingent consideration		$ 12,500
Consideration receivable, economic adjustment			$ 11,189
Consideration received for working capital adjustments			$ 124
Consideration due for expected future post-employment benefits	200
Consideration received for expected future post-employment benefits	$ 2,400

Fair value measurements (Detail

Fair value measurements (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
ASSETS:
Cash equivalents	$ 120,061	$ 102,675
Trust assets	4,789	5,226
Surety bonds	1,870	1,870
TOTAL	126,720	109,771
LIABILITIES:
E.ON contingent obligation - net	0	0
TOTAL	0	0
Fair Value, Inputs, Level 1 [Member]
ASSETS:
Cash equivalents	120,061	102,675
Trust assets	4,789	5,226
Surety bonds	1,870	1,870
TOTAL	126,720	109,771
LIABILITIES:
E.ON contingent obligation - net	0	0
TOTAL	0	0
Fair Value, Inputs, Level 2 [Member]
ASSETS:
Cash equivalents	0	0
Trust assets	0	0
Surety bonds	0	0
TOTAL	0	0
LIABILITIES:
E.ON contingent obligation - net	0	0
TOTAL	0	0
Fair Value, Inputs, Level 3 [Member]
ASSETS:
Cash equivalents	0	0
Trust assets	0	0
Surety bonds	0	0
TOTAL	0	0
LIABILITIES:
E.ON contingent obligation - net	0	0
TOTAL	$ 0	$ 0

Earnings (loss) per share (Deta

Earnings (loss) per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share [Abstract]
Net income (loss)	$ (16,163)	$ 73,779
Amount allocated to common stockholders (in hundredths)	100.00%	91.91%
Basic EPS:
Net income (loss) allocated to common stockholders	$ (16,163)	$ 67,813
Net income (loss) allocated to common stockholders - (shares)	87,040,000	88,814,000
Net income (loss) allocated to common stockholders (in dollars per share)	$ (0.19)	$ 0.76
Effect of Dilutive Securities:
Share-based compensation plans	$ 0	$ 0
Share-based compensation plans - (shares)	0	555,000
Diluted EPS:
Net income (loss) allocated to common stockholders with assumed conversion	$ (16,163)	$ 67,813
Net income (loss) allocated to common stockholders with assumed conversion - (shares)	87,040,000	89,369,000
Net income (loss) allocated to common stockholders with assumed conversion (in dollars per share)	$ (0.19)	$ 0.76
Stock options [Member]
Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from calculation of diluted EPS (shares)	393,237	333,266
Service-based share awards [Member]
Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from calculation of diluted EPS (shares)	498,809	0

Shareholders' equity (Details)

Shareholders' equity (Details) - USD ($)	3 Months Ended		12 Months Ended	60 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2011	Dec. 31, 2008
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	195,000,000		195,000,000	195,000,000
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01	$ 0.001
Common stock, shares issued	94,246,254		94,246,254	94,224,571
Common stock, shares outstanding	87,059,733		87,059,733	87,038,050
Stock repurchase program, authorized amount				$ 130,000,000	$ 60,000,000
Repurchase of common stock (in shares)			0	7,186,521
Repurchase of common stock, aggregate purchase price				$ 86,276,000
Stock repurchase program, remaining authorized repurchase amount	$ 43,724,000		$ 43,724,000
Preferred stock, shares authorized	5,000,000		5,000,000	5,000,000
Preferred stock par value (in dollars per share)	$ 0.01		$ 0.01	$ 0.001
Preferred shares issued						160,000
Number of shares issued for each share of preferred stock	100		100
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)			0	7,186,521
Series A Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Repurchase of common stock (in shares)	0	0
Preferred stock par value (in dollars per share)	$ 0.01		$ 0.01
Preferred shares outstanding	76,446		76,446	76,539
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, Beginning balance (in shares)	76,539	78,141	78,061
Repurchase of common stock (in shares)	0	0
Conversion of convertible preferred stock (in shares)	(93)	(80)
Issuance for stock compensation plans (in shares)	0	0
Shares, Ending balance (in shares)	76,446	78,061	76,446	76,539
Treasury Stock [Member]
Class of Stock [Line Items]
Repurchase of common stock (in shares)	0	1,200,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, Beginning balance (in shares)	7,186,521	4,786,521	5,986,521
Repurchase of common stock (in shares)	0	1,200,000
Conversion of convertible preferred stock (in shares)	0	0
Issuance for stock compensation plans (in shares)	0	0
Shares, Ending balance (in shares)	7,186,521	5,986,521	7,186,521	7,186,521
Common Stock [Member]
Class of Stock [Line Items]
Repurchase of common stock (in shares)	0	(1,200,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, Beginning balance (in shares)	87,038,050	89,064,582	87,883,357
Repurchase of common stock (in shares)	0	(1,200,000)
Conversion of convertible preferred stock (in shares)	9,305	7,947
Issuance for stock compensation plans (in shares)	12,378	10,828
Shares, Ending balance (in shares)	87,059,733	87,883,357	87,059,733	87,038,050

Income taxes (Details)

Income taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ (2,070)	$ 9,301

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Inventory, Net [Abstract]
Raw materials	$ 54,914	$ 52,121
Work-in-process	28,302	34,025
Finished goods	18,821	15,988
Operating and other supplies	118,465	129,738
Total inventories	$ 220,502	$ 231,872

Debt (Details)

Debt (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Jun. 04, 2013
Debt Instrument [Line Items]
Industrial revenue bonds	$ 7,815	$ 7,815
Total debt	255,195	255,093
Long-term Debt [Member] | Senior secured notes due June 01, 2021 [Member]
Debt Instrument [Line Items]
Secured secured notes	$ 247,380	$ 247,278
Maturity date	Jun. 1, 2021	Jun. 1, 2021
Stated interest rate, percentage	7.50%	7.50%	7.50%
Debt discount	$ 2,620	$ 2,722
Short-term Debt [Member] | Industrial revenue bonds due 2028 [Member]
Debt Instrument [Line Items]
Industrial revenue bonds	$ 7,815	$ 7,815
Maturity date	Apr. 1, 2028	Apr. 1, 2028
Effective interest rate, maximum	12.00%	12.00%
Stated interest rate, percentage	0.59%

Debt - Credit Facility (Details

Debt - Credit Facility (Details) - USD ($)	Mar. 31, 2016	Dec. 31, 2015	Nov. 27, 2013	Jun. 04, 2013
Line of Credit Facility [Line Items]
Fair value of debt instrument	$ 184,063,000	$ 169,220,000
U.S. revolving credit facility [Member] | Long-term Debt [Member]
Line of Credit Facility [Line Items]
Credit facility face amount	150,000,000
Credit facility maximum amount	150,000,000
Borrowing availability	85,844,000
Borrowing availability, net of outstanding letters of credit and borrowings	41,085,000
U.S. letter of credit [Member] | Long-term Debt [Member]
Line of Credit Facility [Line Items]
Letter of credit sub-facility amount	110,000,000
Borrowing availability, net of outstanding letters of credit and borrowings	44,759,000
Outstanding borrowings	0
Iceland revolving line of credit [Member] | Long-term Debt [Member]
Line of Credit Facility [Line Items]
Credit facility face amount			$ 50,000,000
Credit facility maximum amount	50,000,000
Borrowing availability	45,397,000
Outstanding borrowings	0
Borrowing availability, net of outstanding letters of credit and borrowings	$ 45,397,000
Senior secured notes due June 01, 2021 [Member] | Long-term Debt [Member]
Line of Credit Facility [Line Items]
Face amount				$ 250,000,000
Stated interest rate, percentage	7.50%	7.50%		7.50%

Commitments and contingencies (

Commitments and contingencies (Details) $ in Thousands	Dec. 18, 2015source	Mar. 31, 2015USD ($)	Apr. 30, 2013USD ($)	Mar. 31, 2016USD ($)LaborUnions	Dec. 31, 2013USD ($)	Mar. 31, 2016USD ($)LaborUnions	Dec. 31, 2015USD ($)	Dec. 31, 2011MW
Environmental Contingencies [Abstract]
Environmental-related accrued liabilities				$ 1,248		$ 1,248	$ 1,112
Environmental remediation expense for Hydrocarbon Recovery Plan						$ 1,085
OR Power Agreement [Abstract]
Power currently available under the power purchase agreement (in megawatts) | MW								47.5
Labor Commitments [Abstract]
Percentage of total work force in union				63.00%		63.00%
Percentage of Grundartangi work force represented by the labor unions (in hundredths)				84.00%		84.00%
Number of labor unions Grundartangi subsidiary entered into a new labor agreement with | LaborUnions				5		5
Percentage of Vlissingen work force represented by the labor union (in hundredths)				100.00%		100.00%
Percentage of U.S. based work force represented by a union (in hundredths)				52.00%		52.00%
PBGC Agreement [Member]
Environmental Contingencies [Abstract]
Required pension contributions above minimum			$ 17,400
Pension contributions above minimum remaining				$ 9,600
Hawesville [Member]
Legal Contingencies [Abstract]
Power supply agreement, termination notice period				1 year
Sebree [Member]
Legal Contingencies [Abstract]
Power supply agreement, termination notice period				1 year
South Carolina Public Service Authority [Member]
Legal Contingencies [Abstract]
Operating capacity under agreement, percentage	50.00%
Number of power sources | source	2
Power agreement, power supply from source one, percentage	25.00%
Power agreement, power supply from source two, percentage	75.00%
Agreement termination notice period	60 days
PBGC Agreement [Member]
Environmental Contingencies [Abstract]
Pension Contributions		$ 1,100			$ 6,700

Components of accumulated oth46

Components of accumulated other comprehensive loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive loss before income tax effect	$ (122,139)		$ (123,345)
Income tax effect	10,312		10,695
Accumulated other comprehensive loss	(111,827)		(112,650)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Equity, beginning balance	1,017,870
Net amount reclassified to net income (loss)	823	$ 78
Equity, ending balance	1,002,851
Defined benefit plan and other postretirement liabilities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive loss before income tax effect	(120,658)		(121,910)
Income tax effect	10,852		11,243
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Equity, beginning balance	(110,667)	(115,852)
Net amount reclassified to net income (loss)	861	117
Equity, ending balance	(109,806)	(115,735)
Unrealized loss on financial instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive loss before income tax effect	(1,481)		(1,435)
Income tax effect	(540)		$ (548)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Equity, beginning balance	(1,983)	(1,830)
Net amount reclassified to net income (loss)	(38)	(39)
Equity, ending balance	(2,021)	(1,869)
AOCI Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Equity, beginning balance	(112,650)	(117,682)
Equity, ending balance	$ (111,827)	$ (117,604)

Components of accumulated oth47

Components of accumulated other comprehensive loss - Reclassifications out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of goods sold	$ 321,906	$ 493,816
Selling, general and administrative expenses	9,625	11,971
Other operating expense, net	(881)	(2,079)
Income tax benefit (expense)	2,070	(9,301)
Net income (loss)	(16,163)	73,779
Reclassification out of Accumulated Other Comprehensive Income [Member] | Defined benefit plan and other postretirement liabilities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of goods sold	777	325
Selling, general and administrative expenses	125	183
Other operating expense, net	350	0
Income tax benefit (expense)	(391)	(391)
Net income (loss)	861	117
Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized loss on financial instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of goods sold	(46)	(47)
Income tax benefit (expense)	8	8
Net income (loss)	$ (38)	$ (39)

Components of net periodic be48

Components of net periodic benefit cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 1,270	$ 1,704
Interest cost	3,480	3,388
Expected return on plan assets	(4,816)	(5,494)
Amortization of prior service costs	28	25
Amortization of net loss	1,043	620
Net periodic benefit cost	1,005	243
Employer contributions	464
Other Postretirement Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	330	562
Interest cost	1,456	1,591
Amortization of prior service costs	(695)	(961)
Amortization of net loss	876	865
Net periodic benefit cost	$ 1,967	$ 2,057

Restricted Cash (Details)

Restricted Cash (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Apr. 30, 2015	Mar. 31, 2016	Mar. 31, 2015
Cash and Cash Equivalents [Abstract]
Restricted cash			$ 21,000
Decrease in restricted cash	$ 21,000	$ 0	$ (21,012)

Supplemental cash flow inform50

Supplemental cash flow information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash paid for:
Interest	$ 160	$ 5
Income taxes	2,596	1,142
Non-cash investing activities:
Accrued capital costs	$ 206	$ 1,202

Condensed consolidating finan51

Condensed consolidating financial information - Statement of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenue, Net [Abstract]
Related parties	$ 280,377	$ 575,729
Third-party customers	38,477	12,182
Total net sales	318,854	587,911
Cost of goods sold	321,906	493,816
Gross profit (loss)	(3,052)	94,095
Selling, general and administrative expenses	9,625	11,971
Other operating expense - net	881	2,079
Operating income (loss)	(13,558)	80,045
Interest expense - third parties	(5,493)	(5,551)
Interest income (expense) - affiliates	0	0
Interest income - third parties	114	142
Net gain on forward and derivative contracts	353	353
Unrealized gain on fair value of contingent consideration	0	6,527
Other income (expense) - net	(6)	1,054
Income (loss) before income taxes and equity in earnings of joint ventures	(18,590)	82,570
Income tax benefit	2,070	(9,301)
Income (loss) before equity in earnings of joint ventures	(16,520)	73,269
Equity in earnings (loss) of joint ventures	357	510
Net income (loss)	(16,163)	73,779
Other comprehensive income before income tax effect	1,206	461
Income tax effect	(383)	(383)
Other comprehensive income	823	78
Total comprehensive income (loss)	(15,340)	73,857
Consolidating Adjustments [Member]
Revenue, Net [Abstract]
Related parties	(23,397)	(1,114)
Third-party customers	0	(698)
Total net sales	(23,397)	(1,812)
Cost of goods sold	(23,971)	(4,514)
Gross profit (loss)	574	2,702
Selling, general and administrative expenses	0	1,000
Other operating expense - net	0	0
Operating income (loss)	574	1,702
Interest expense - third parties	0	0
Interest income (expense) - affiliates	0	0
Interest income - third parties	0	0
Net gain on forward and derivative contracts	0	0
Unrealized gain on fair value of contingent consideration		0
Other income (expense) - net	0	(1,730)
Income (loss) before income taxes and equity in earnings of joint ventures	574	(28)
Income tax benefit	0	50
Income (loss) before equity in earnings of joint ventures	574	22
Equity in earnings (loss) of joint ventures	13,775	(79,246)
Net income (loss)	14,349	(79,224)
Other comprehensive income before income tax effect	(1,081)	(278)
Income tax effect	(8)	(8)
Other comprehensive income	(1,089)	(286)
Total comprehensive income (loss)	13,260	(79,510)
The Company [Member]
Revenue, Net [Abstract]
Related parties	0	0
Third-party customers	0	0
Total net sales	0	0
Cost of goods sold	0	0
Gross profit (loss)	0	0
Selling, general and administrative expenses	8,299	10,837
Other operating expense - net	0	0
Operating income (loss)	(8,299)	(10,837)
Interest expense - third parties	(5,065)	(5,109)
Interest income (expense) - affiliates	9,548	10,226
Interest income - third parties	37	15
Net gain on forward and derivative contracts	0	0
Unrealized gain on fair value of contingent consideration		0
Other income (expense) - net	771	537
Income (loss) before income taxes and equity in earnings of joint ventures	(3,008)	(5,168)
Income tax benefit	620	(299)
Income (loss) before equity in earnings of joint ventures	(2,388)	(5,467)
Equity in earnings (loss) of joint ventures	(13,775)	79,246
Net income (loss)	(16,163)	73,779
Other comprehensive income before income tax effect	1,206	461
Income tax effect	(383)	(383)
Other comprehensive income	823	78
Total comprehensive income (loss)	$ (15,340)	73,857
Combined Guarantor Subsidiaries [Member]
Condensed Statement of Income Captions [Line Items]
Ownership percentage	100.00%
Revenue, Net [Abstract]
Related parties	$ 162,120	403,064
Third-party customers	38,468	12,874
Total net sales	200,588	415,938
Cost of goods sold	209,573	362,302
Gross profit (loss)	(8,985)	53,636
Selling, general and administrative expenses	0	(944)
Other operating expense - net	0	0
Operating income (loss)	(8,985)	54,580
Interest expense - third parties	(382)	(396)
Interest income (expense) - affiliates	0	0
Interest income - third parties	0	4
Net gain on forward and derivative contracts	353	353
Unrealized gain on fair value of contingent consideration		6,527
Other income (expense) - net	(6)	(484)
Income (loss) before income taxes and equity in earnings of joint ventures	(9,020)	60,584
Income tax benefit	0	0
Income (loss) before equity in earnings of joint ventures	(9,020)	60,584
Equity in earnings (loss) of joint ventures	0	0
Net income (loss)	(9,020)	60,584
Other comprehensive income before income tax effect	778	33
Income tax effect	0	0
Other comprehensive income	778	33
Total comprehensive income (loss)	(8,242)	60,617
Combined Non-Guarantor Subsidiaries [Member]
Revenue, Net [Abstract]
Related parties	141,654	173,779
Third-party customers	9	6
Total net sales	141,663	173,785
Cost of goods sold	136,304	136,028
Gross profit (loss)	5,359	37,757
Selling, general and administrative expenses	1,326	1,078
Other operating expense - net	881	2,079
Operating income (loss)	3,152	34,600
Interest expense - third parties	(46)	(46)
Interest income (expense) - affiliates	(9,548)	(10,226)
Interest income - third parties	77	123
Net gain on forward and derivative contracts	0	0
Unrealized gain on fair value of contingent consideration		0
Other income (expense) - net	(771)	2,731
Income (loss) before income taxes and equity in earnings of joint ventures	(7,136)	27,182
Income tax benefit	1,450	(9,052)
Income (loss) before equity in earnings of joint ventures	(5,686)	18,130
Equity in earnings (loss) of joint ventures	357	510
Net income (loss)	(5,329)	18,640
Other comprehensive income before income tax effect	303	245
Income tax effect	8	8
Other comprehensive income	311	253
Total comprehensive income (loss)	$ (5,018)	$ 18,893

Condensed consolidating finan52

Condensed consolidating financial information - Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Condensed Balance Sheet Statements, Captions [Line Items]
Cash & cash equivalents	$ 126,461	$ 115,393	$ 226,431	$ 163,242
Restricted cash	795	791
Accounts receivable - net	12,668	9,475
Due from affiliates	15,478	17,417
Inventories	220,502	231,872
Prepaid and other current assets	29,622	42,412
Assets held for sale	29,715	30,697
Total current assets	435,241	448,057
Property, plant and equipment - net	1,215,222	1,232,256
Investment in subsidiaries	0	0
Due from affiliates - less current portion	0	0
Other assets	73,142	72,155
TOTAL	1,723,605	1,752,468
Accounts payable, trade	84,587	90,489
Due to affiliates	6,173	10,045
Accrued and other current liabilities	50,169	48,822
Accrued employee benefits costs	10,054	10,148
Industrial revenue bonds	7,815	7,815
Total current liabilities	158,798	167,319
Senior notes payable	247,380	247,278
Accrued pension benefits costs cost - less current portion	43,437	43,999
Accrued postretirement benefits costs - less current portion	125,941	125,999
Other liabilities	51,799	53,009
Intercompany loan	0	0
Deferred taxes	93,399	96,994
Total noncurrent liabilities	561,956	567,279
Series A Preferred stock	1	1
Common stock	942	942
Additional paid-in capital	2,513,952	2,513,631
Treasury stock, at cost	(86,276)	(86,276)
Accumulated other comprehensive loss	(111,827)	(112,650)
Accumulated deficit	(1,313,941)	(1,297,778)
Total shareholders’ equity	1,002,851	1,017,870
TOTAL	1,723,605	1,752,468
Consolidating Adjustments [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash & cash equivalents	0	0	0	0
Restricted cash	0	0
Accounts receivable - net	0	0
Due from affiliates	0	0
Inventories	(2,274)	(2,525)
Prepaid and other current assets	0	0
Assets held for sale	0	0
Total current assets	(2,274)	(2,525)
Property, plant and equipment - net	0	0
Investment in subsidiaries	(580,999)	(593,604)
Due from affiliates - less current portion	(639,780)	(632,170)
Other assets	7,418	7,419
TOTAL	(1,215,635)	(1,220,880)
Accounts payable, trade	0	0
Due to affiliates	2,916	0
Accrued and other current liabilities	0	0
Accrued employee benefits costs	0	0
Industrial revenue bonds	0	0
Total current liabilities	2,916	0
Senior notes payable	0	0
Accrued pension benefits costs cost - less current portion	0	0
Accrued postretirement benefits costs - less current portion	0	0
Other liabilities	7,418	7,418
Intercompany loan	(644,696)	(634,170)
Deferred taxes	0	0
Total noncurrent liabilities	(637,278)	(626,752)
Series A Preferred stock	0	0
Common stock	(228,424)	(224,424)
Additional paid-in capital	(2,373,556)	(2,229,161)
Treasury stock, at cost	0	0
Accumulated other comprehensive loss	0	0
Accumulated deficit	2,020,707	1,859,457
Total shareholders’ equity	(581,273)	(594,128)
TOTAL	(1,215,635)	(1,220,880)
The Company [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash & cash equivalents	49,667	58,421	164,075	70,683
Restricted cash	0	0
Accounts receivable - net	0	104
Due from affiliates	382	13
Inventories	180	180
Prepaid and other current assets	7,073	7,713
Assets held for sale	0	0
Total current assets	57,302	66,431
Property, plant and equipment - net	8,863	9,188
Investment in subsidiaries	580,999	593,604
Due from affiliates - less current portion	639,780	632,170
Other assets	30,025	29,536
TOTAL	1,316,969	1,330,929
Accounts payable, trade	2,582	2,380
Due to affiliates	1,500	2,143
Accrued and other current liabilities	14,280	11,247
Accrued employee benefits costs	1,824	1,824
Industrial revenue bonds	0	0
Total current liabilities	20,186	17,594
Senior notes payable	247,380	247,278
Accrued pension benefits costs cost - less current portion	39,552	39,831
Accrued postretirement benefits costs - less current portion	4,834	4,524
Other liabilities	1,893	3,307
Intercompany loan	0	0
Deferred taxes	0	0
Total noncurrent liabilities	293,659	294,940
Series A Preferred stock	1	1
Common stock	942	942
Additional paid-in capital	2,513,952	2,513,631
Treasury stock, at cost	(86,276)	(86,276)
Accumulated other comprehensive loss	(13,391)	(13,125)
Accumulated deficit	(1,412,104)	(1,396,778)
Total shareholders’ equity	1,003,124	1,018,395
TOTAL	1,316,969	1,330,929
Combined Guarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash & cash equivalents	(74)	(3,647)	(64)	(1,187)
Restricted cash	795	791
Accounts receivable - net	12,088	8,891
Due from affiliates	13,955	14,493
Inventories	142,070	148,280
Prepaid and other current assets	4,290	16,242
Assets held for sale	0	0
Total current assets	173,124	185,050
Property, plant and equipment - net	352,384	361,626
Investment in subsidiaries	0	0
Due from affiliates - less current portion	0	0
Other assets	19,328	19,153
TOTAL	544,836	565,829
Accounts payable, trade	47,777	53,145
Due to affiliates	1,210	7,167
Accrued and other current liabilities	11,073	14,759
Accrued employee benefits costs	7,550	7,644
Industrial revenue bonds	7,815	7,815
Total current liabilities	75,425	90,530
Senior notes payable	0	0
Accrued pension benefits costs cost - less current portion	(11,009)	(11,021)
Accrued postretirement benefits costs - less current portion	119,529	119,911
Other liabilities	30,749	30,505
Intercompany loan	126,343	124,518
Deferred taxes	0	0
Total noncurrent liabilities	265,612	263,913
Series A Preferred stock	0	0
Common stock	0	0
Additional paid-in capital	191,023	191,023
Treasury stock, at cost	0	0
Accumulated other comprehensive loss	(59,249)	(60,026)
Accumulated deficit	72,025	80,389
Total shareholders’ equity	203,799	211,386
TOTAL	544,836	565,829
Combined Non-Guarantor Subsidiaries [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Cash & cash equivalents	76,868	60,619	$ 62,420	$ 93,746
Restricted cash	0	0
Accounts receivable - net	580	480
Due from affiliates	1,141	2,911
Inventories	80,526	85,937
Prepaid and other current assets	18,259	18,457
Assets held for sale	29,715	30,697
Total current assets	207,089	199,101
Property, plant and equipment - net	853,975	861,442
Investment in subsidiaries	0	0
Due from affiliates - less current portion	0	0
Other assets	16,371	16,047
TOTAL	1,077,435	1,076,590
Accounts payable, trade	34,228	34,964
Due to affiliates	547	735
Accrued and other current liabilities	24,816	22,816
Accrued employee benefits costs	680	680
Industrial revenue bonds	0	0
Total current liabilities	60,271	59,195
Senior notes payable	0	0
Accrued pension benefits costs cost - less current portion	14,894	15,189
Accrued postretirement benefits costs - less current portion	1,578	1,564
Other liabilities	11,739	11,779
Intercompany loan	518,353	509,652
Deferred taxes	93,399	96,994
Total noncurrent liabilities	639,963	635,178
Series A Preferred stock	0	0
Common stock	228,424	224,424
Additional paid-in capital	2,182,533	2,038,138
Treasury stock, at cost	0	0
Accumulated other comprehensive loss	(39,187)	(39,499)
Accumulated deficit	(1,994,569)	(1,840,846)
Total shareholders’ equity	377,201	382,217
TOTAL	$ 1,077,435	$ 1,076,590

Condensed consolidating finan53

Condensed consolidating financial information - Cash Flows (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Apr. 30, 2015	Mar. 31, 2016	Mar. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities		$ 14,903	$ 116,267
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchase of property, plant and equipment		(3,835)	(12,627)
Restricted and other cash deposits	$ 21,000	0	(21,012)
Net cash used in investing activities		(3,835)	(33,639)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Borrowings under revolving credit facilities		371	455
Repayments under revolving credit facilities		(371)	(455)
Repurchase of common stock		0	(19,439)
Intercompany transactions		0	0
Net cash used in financing activities		0	(19,439)
CHANGE IN CASH AND CASH EQUIVALENTS		11,068	63,189
Cash and cash equivalents, beginning of period	226,431	115,393	163,242
Cash and cash equivalents, end of period		126,461	226,431
Consolidating Adjustments [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities		8,266	185,624
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchase of property, plant and equipment		0	0
Restricted and other cash deposits			0
Net cash used in investing activities		0	0
Net Cash Provided by (Used in) Financing Activities [Abstract]
Borrowings under revolving credit facilities		0	0
Repayments under revolving credit facilities		0	0
Repurchase of common stock			0
Intercompany transactions		(8,266)	(185,624)
Net cash used in financing activities		(8,266)	(185,624)
CHANGE IN CASH AND CASH EQUIVALENTS		0	0
Cash and cash equivalents, beginning of period	0	0	0
Cash and cash equivalents, end of period		0	0
The Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities		(8,754)	113,179
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchase of property, plant and equipment		0	(348)
Restricted and other cash deposits			0
Net cash used in investing activities		0	(348)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Borrowings under revolving credit facilities		371	455
Repayments under revolving credit facilities		(371)	(455)
Repurchase of common stock			(19,439)
Intercompany transactions		0	0
Net cash used in financing activities		0	(19,439)
CHANGE IN CASH AND CASH EQUIVALENTS		(8,754)	93,392
Cash and cash equivalents, beginning of period	164,075	58,421	70,683
Cash and cash equivalents, end of period		49,667	164,075
Combined Guarantor Subsidiaries [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities		5,435	40,025
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchase of property, plant and equipment		(1,426)	(6,726)
Restricted and other cash deposits			(21,012)
Net cash used in investing activities		(1,426)	(27,738)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Borrowings under revolving credit facilities		0	0
Repayments under revolving credit facilities		0	0
Repurchase of common stock			0
Intercompany transactions		(436)	(11,164)
Net cash used in financing activities		(436)	(11,164)
CHANGE IN CASH AND CASH EQUIVALENTS		3,573	1,123
Cash and cash equivalents, beginning of period	(64)	(3,647)	(1,187)
Cash and cash equivalents, end of period		(74)	(64)
Combined Non-Guarantor Subsidiaries [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net cash provided by (used in) operating activities		9,956	(222,561)
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchase of property, plant and equipment		(2,409)	(5,553)
Restricted and other cash deposits			0
Net cash used in investing activities		(2,409)	(5,553)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Borrowings under revolving credit facilities		0	0
Repayments under revolving credit facilities		0	0
Repurchase of common stock			0
Intercompany transactions		8,702	196,788
Net cash used in financing activities		8,702	196,788
CHANGE IN CASH AND CASH EQUIVALENTS		16,249	(31,326)
Cash and cash equivalents, beginning of period	$ 62,420	60,619	93,746
Cash and cash equivalents, end of period		$ 76,868	$ 62,420